diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 3ea4894..b86d586 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -14,14 +14,14 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: setup rust toolchain
-        run: rustup show
+        run: rustup toolchain install
       - uses: taiki-e/install-action@nextest
       - uses: taiki-e/install-action@mdbook
       - name: patch for gh-pages build
         run: mv mini-lsm-book/theme/head.hbs._ mini-lsm-book/theme/head.hbs
       - name: check and build
         run: cargo x ci
-      - uses: actions/upload-pages-artifact@v1
+      - uses: actions/upload-pages-artifact@v3
         with:
           path: mini-lsm-book/book
 
@@ -38,4 +38,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v1
+        uses: actions/deploy-pages@v4
diff --git a/Cargo.toml b/Cargo.toml
index 9d968d6..edfbb47 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,7 +4,7 @@ resolver = "2"
 
 [workspace.package]
 version = "0.2.0"
-edition = "2021"
+edition = "2024"
 homepage = "https://github.com/skyzh/mini-lsm"
 keywords = ["storage", "database", "tutorial", "course"]
 license = "Apache-2.0"
diff --git a/mini-lsm-book/src/week1-01-memtable.md b/mini-lsm-book/src/week1-01-memtable.md
index 991beb4..50a2f25 100644
--- a/mini-lsm-book/src/week1-01-memtable.md
+++ b/mini-lsm-book/src/week1-01-memtable.md
@@ -33,7 +33,7 @@ crossbeam-skiplist provides similar interfaces to the Rust std's `BTreeMap`: ins
 
 You will also notice that the `MemTable` structure does not have a `delete` interface. In the mini-lsm implementation, deletion is represented as a key corresponding to an empty value.
 
-In this task, you will need to implement `MemTable::get` and `MemTable::put` to enable modifications of the memtable.
+In this task, you will need to implement `MemTable::get` and `MemTable::put` to enable modifications of the memtable. Note that `put` should always overwrite a key if it already exists. You won't have mutiple entries of the same key in a single memtable.
 
 We use the `bytes` crate for storing the data in the memtable. `bytes::Byte` is similar to `Arc<[u8]>`. When you clone the `Bytes`, or get a slice of `Bytes`, the underlying data will not be copied, and therefore cloning it is cheap. Instead, it simply creates a new reference to the storage area and the storage area will be freed when there are no reference to that area.
 
@@ -157,6 +157,7 @@ Now that you have multiple memtables, you may modify your read path `get` functi
 ## Test Your Understanding
 
 * Why doesn't the memtable provide a `delete` API?
+* Does it make sense for the memtable to store all write operations instead of only the latest version of a key? For example, the user puts a->1, a->2, and a->3 into the same memtable.
 * Is it possible to use other data structures as the memtable in LSM? What are the pros/cons of using the skiplist?
 * Why do we need a combination of `state` and `state_lock`? Can we only use `state.read()` and `state.write()`?
 * Why does the order to store and to probe the memtables matter? If a key appears in multiple memtables, which version should you return to the user?
diff --git a/mini-lsm-mvcc/src/compact.rs b/mini-lsm-mvcc/src/compact.rs
index 83e9654..5b9f736 100644
--- a/mini-lsm-mvcc/src/compact.rs
+++ b/mini-lsm-mvcc/src/compact.rs
@@ -28,10 +28,10 @@ pub use simple_leveled::{
 };
 pub use tiered::{TieredCompactionController, TieredCompactionOptions, TieredCompactionTask};
 
+use crate::iterators::StorageIterator;
 use crate::iterators::concat_iterator::SstConcatIterator;
 use crate::iterators::merge_iterator::MergeIterator;
 use crate::iterators::two_merge_iterator::TwoMergeIterator;
-use crate::iterators::StorageIterator;
 use crate::key::KeySlice;
 use crate::lsm_storage::{CompactionFilter, LsmStorageInner, LsmStorageState};
 use crate::manifest::ManifestRecord;
diff --git a/mini-lsm-mvcc/src/iterators/merge_iterator.rs b/mini-lsm-mvcc/src/iterators/merge_iterator.rs
index a4cc3c0..02361d7 100644
--- a/mini-lsm-mvcc/src/iterators/merge_iterator.rs
+++ b/mini-lsm-mvcc/src/iterators/merge_iterator.rs
@@ -13,8 +13,8 @@
 // limitations under the License.
 
 use std::cmp::{self};
-use std::collections::binary_heap::PeekMut;
 use std::collections::BinaryHeap;
+use std::collections::binary_heap::PeekMut;
 
 use anyhow::Result;
 
diff --git a/mini-lsm-mvcc/src/iterators/two_merge_iterator.rs b/mini-lsm-mvcc/src/iterators/two_merge_iterator.rs
index a6feaa9..7b4ef8b 100644
--- a/mini-lsm-mvcc/src/iterators/two_merge_iterator.rs
+++ b/mini-lsm-mvcc/src/iterators/two_merge_iterator.rs
@@ -25,9 +25,9 @@ pub struct TwoMergeIterator<A: StorageIterator, B: StorageIterator> {
 }
 
 impl<
-        A: 'static + StorageIterator,
-        B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
-    > TwoMergeIterator<A, B>
+    A: 'static + StorageIterator,
+    B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
+> TwoMergeIterator<A, B>
 {
     fn choose_a(a: &A, b: &B) -> bool {
         if !a.is_valid() {
@@ -59,9 +59,9 @@ impl<
 }
 
 impl<
-        A: 'static + StorageIterator,
-        B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
-    > StorageIterator for TwoMergeIterator<A, B>
+    A: 'static + StorageIterator,
+    B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
+> StorageIterator for TwoMergeIterator<A, B>
 {
     type KeyType<'a> = A::KeyType<'a>;
 
diff --git a/mini-lsm-mvcc/src/lsm_iterator.rs b/mini-lsm-mvcc/src/lsm_iterator.rs
index 1e04f20..f71225d 100644
--- a/mini-lsm-mvcc/src/lsm_iterator.rs
+++ b/mini-lsm-mvcc/src/lsm_iterator.rs
@@ -14,13 +14,13 @@
 
 use std::ops::Bound;
 
-use anyhow::{bail, Result};
+use anyhow::{Result, bail};
 use bytes::Bytes;
 
+use crate::iterators::StorageIterator;
 use crate::iterators::concat_iterator::SstConcatIterator;
 use crate::iterators::merge_iterator::MergeIterator;
 use crate::iterators::two_merge_iterator::TwoMergeIterator;
-use crate::iterators::StorageIterator;
 use crate::mem_table::MemTableIterator;
 use crate::table::SsTableIterator;
 
diff --git a/mini-lsm-mvcc/src/lsm_storage.rs b/mini-lsm-mvcc/src/lsm_storage.rs
index 77247dd..3705da9 100644
--- a/mini-lsm-mvcc/src/lsm_storage.rs
+++ b/mini-lsm-mvcc/src/lsm_storage.rs
@@ -16,8 +16,8 @@ use std::collections::{BTreeSet, HashMap};
 use std::fs::File;
 use std::ops::Bound;
 use std::path::{Path, PathBuf};
-use std::sync::atomic::AtomicUsize;
 use std::sync::Arc;
+use std::sync::atomic::AtomicUsize;
 
 use anyhow::{Context, Result};
 use bytes::Bytes;
@@ -28,16 +28,16 @@ use crate::compact::{
     CompactionController, CompactionOptions, LeveledCompactionController, LeveledCompactionOptions,
     SimpleLeveledCompactionController, SimpleLeveledCompactionOptions, TieredCompactionController,
 };
+use crate::iterators::StorageIterator;
 use crate::iterators::concat_iterator::SstConcatIterator;
 use crate::iterators::merge_iterator::MergeIterator;
 use crate::iterators::two_merge_iterator::TwoMergeIterator;
-use crate::iterators::StorageIterator;
 use crate::key::{self, KeySlice};
 use crate::lsm_iterator::{FusedIterator, LsmIterator};
 use crate::manifest::{Manifest, ManifestRecord};
-use crate::mem_table::{map_bound, map_key_bound_plus_ts, MemTable};
-use crate::mvcc::txn::{Transaction, TxnIterator};
+use crate::mem_table::{MemTable, map_bound, map_key_bound_plus_ts};
 use crate::mvcc::LsmMvccInner;
+use crate::mvcc::txn::{Transaction, TxnIterator};
 use crate::table::{FileObject, SsTable, SsTableBuilder, SsTableIterator};
 
 pub type BlockCache = moka::sync::Cache<(usize, usize), Arc<Block>>;
diff --git a/mini-lsm-mvcc/src/manifest.rs b/mini-lsm-mvcc/src/manifest.rs
index f13ff5f..0cad63f 100644
--- a/mini-lsm-mvcc/src/manifest.rs
+++ b/mini-lsm-mvcc/src/manifest.rs
@@ -17,7 +17,7 @@ use std::io::{Read, Write};
 use std::path::Path;
 use std::sync::Arc;
 
-use anyhow::{bail, Context, Result};
+use anyhow::{Context, Result, bail};
 use bytes::{Buf, BufMut};
 use parking_lot::{Mutex, MutexGuard};
 use serde::{Deserialize, Serialize};
diff --git a/mini-lsm-mvcc/src/mem_table.rs b/mini-lsm-mvcc/src/mem_table.rs
index 79480cd..5a5102b 100644
--- a/mini-lsm-mvcc/src/mem_table.rs
+++ b/mini-lsm-mvcc/src/mem_table.rs
@@ -14,13 +14,13 @@
 
 use std::ops::Bound;
 use std::path::Path;
-use std::sync::atomic::AtomicUsize;
 use std::sync::Arc;
+use std::sync::atomic::AtomicUsize;
 
 use anyhow::Result;
 use bytes::Bytes;
-use crossbeam_skiplist::map::Entry;
 use crossbeam_skiplist::SkipMap;
+use crossbeam_skiplist::map::Entry;
 use ouroboros::self_referencing;
 
 use crate::iterators::StorageIterator;
diff --git a/mini-lsm-mvcc/src/mvcc.rs b/mini-lsm-mvcc/src/mvcc.rs
index 7f9f02a..3d31957 100644
--- a/mini-lsm-mvcc/src/mvcc.rs
+++ b/mini-lsm-mvcc/src/mvcc.rs
@@ -20,7 +20,7 @@ pub mod watermark;
 
 use std::{
     collections::{BTreeMap, HashSet},
-    sync::{atomic::AtomicBool, Arc},
+    sync::{Arc, atomic::AtomicBool},
 };
 
 use crossbeam_skiplist::SkipMap;
diff --git a/mini-lsm-mvcc/src/mvcc/txn.rs b/mini-lsm-mvcc/src/mvcc/txn.rs
index f1adbb9..7165342 100644
--- a/mini-lsm-mvcc/src/mvcc/txn.rs
+++ b/mini-lsm-mvcc/src/mvcc/txn.rs
@@ -16,19 +16,19 @@ use std::{
     collections::HashSet,
     ops::Bound,
     sync::{
-        atomic::{AtomicBool, Ordering},
         Arc,
+        atomic::{AtomicBool, Ordering},
     },
 };
 
-use anyhow::{bail, Result};
+use anyhow::{Result, bail};
 use bytes::Bytes;
-use crossbeam_skiplist::{map::Entry, SkipMap};
+use crossbeam_skiplist::{SkipMap, map::Entry};
 use ouroboros::self_referencing;
 use parking_lot::Mutex;
 
 use crate::{
-    iterators::{two_merge_iterator::TwoMergeIterator, StorageIterator},
+    iterators::{StorageIterator, two_merge_iterator::TwoMergeIterator},
     lsm_iterator::{FusedIterator, LsmIterator},
     lsm_storage::{LsmStorageInner, WriteBatchRecord},
     mem_table::map_bound,
diff --git a/mini-lsm-mvcc/src/table.rs b/mini-lsm-mvcc/src/table.rs
index 5d5747f..c6fa4cc 100644
--- a/mini-lsm-mvcc/src/table.rs
+++ b/mini-lsm-mvcc/src/table.rs
@@ -20,7 +20,7 @@ use std::fs::File;
 use std::path::Path;
 use std::sync::Arc;
 
-use anyhow::{anyhow, bail, Result};
+use anyhow::{Result, anyhow, bail};
 pub use builder::SsTableBuilder;
 use bytes::{Buf, BufMut};
 pub use iterator::SsTableIterator;
diff --git a/mini-lsm-mvcc/src/table/bloom.rs b/mini-lsm-mvcc/src/table/bloom.rs
index ddeac13..0a0e5fc 100644
--- a/mini-lsm-mvcc/src/table/bloom.rs
+++ b/mini-lsm-mvcc/src/table/bloom.rs
@@ -14,7 +14,7 @@
 
 // Copyright 2021 TiKV Project Authors. Licensed under Apache-2.0.
 
-use anyhow::{bail, Result};
+use anyhow::{Result, bail};
 use bytes::{Buf, BufMut, Bytes, BytesMut};
 
 /// Implements a bloom filter
diff --git a/mini-lsm-mvcc/src/wal.rs b/mini-lsm-mvcc/src/wal.rs
index d89b6b1..c4aa6bb 100644
--- a/mini-lsm-mvcc/src/wal.rs
+++ b/mini-lsm-mvcc/src/wal.rs
@@ -18,7 +18,7 @@ use std::io::{BufWriter, Read, Write};
 use std::path::Path;
 use std::sync::Arc;
 
-use anyhow::{bail, Context, Result};
+use anyhow::{Context, Result, bail};
 use bytes::{Buf, BufMut, Bytes};
 use crossbeam_skiplist::SkipMap;
 use parking_lot::Mutex;
diff --git a/mini-lsm-starter/Cargo.toml b/mini-lsm-starter/Cargo.toml
index e84ac93..1c90263 100644
--- a/mini-lsm-starter/Cargo.toml
+++ b/mini-lsm-starter/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "mini-lsm-starter"
 version = "0.2.0"
-edition = "2021"
+edition = "2024"
 publish = false
 
 [dependencies]
diff --git a/mini-lsm-starter/src/iterators/two_merge_iterator.rs b/mini-lsm-starter/src/iterators/two_merge_iterator.rs
index a6769e5..c65bff4 100644
--- a/mini-lsm-starter/src/iterators/two_merge_iterator.rs
+++ b/mini-lsm-starter/src/iterators/two_merge_iterator.rs
@@ -28,9 +28,9 @@ pub struct TwoMergeIterator<A: StorageIterator, B: StorageIterator> {
 }
 
 impl<
-        A: 'static + StorageIterator,
-        B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
-    > TwoMergeIterator<A, B>
+    A: 'static + StorageIterator,
+    B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
+> TwoMergeIterator<A, B>
 {
     pub fn create(a: A, b: B) -> Result<Self> {
         unimplemented!()
@@ -38,9 +38,9 @@ impl<
 }
 
 impl<
-        A: 'static + StorageIterator,
-        B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
-    > StorageIterator for TwoMergeIterator<A, B>
+    A: 'static + StorageIterator,
+    B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
+> StorageIterator for TwoMergeIterator<A, B>
 {
     type KeyType<'a> = A::KeyType<'a>;
 
diff --git a/mini-lsm-starter/src/lsm_iterator.rs b/mini-lsm-starter/src/lsm_iterator.rs
index 7e3e2c3..29c589d 100644
--- a/mini-lsm-starter/src/lsm_iterator.rs
+++ b/mini-lsm-starter/src/lsm_iterator.rs
@@ -18,7 +18,7 @@
 use anyhow::Result;
 
 use crate::{
-    iterators::{merge_iterator::MergeIterator, StorageIterator},
+    iterators::{StorageIterator, merge_iterator::MergeIterator},
     mem_table::MemTableIterator,
 };
 
diff --git a/mini-lsm-starter/src/lsm_storage.rs b/mini-lsm-starter/src/lsm_storage.rs
index 503b130..1f8c2e9 100644
--- a/mini-lsm-starter/src/lsm_storage.rs
+++ b/mini-lsm-starter/src/lsm_storage.rs
@@ -18,8 +18,8 @@
 use std::collections::HashMap;
 use std::ops::Bound;
 use std::path::{Path, PathBuf};
-use std::sync::atomic::AtomicUsize;
 use std::sync::Arc;
+use std::sync::atomic::AtomicUsize;
 
 use anyhow::Result;
 use bytes::Bytes;
diff --git a/mini-lsm-starter/src/mem_table.rs b/mini-lsm-starter/src/mem_table.rs
index b847d90..ab559f6 100644
--- a/mini-lsm-starter/src/mem_table.rs
+++ b/mini-lsm-starter/src/mem_table.rs
@@ -17,8 +17,8 @@
 
 use std::ops::Bound;
 use std::path::Path;
-use std::sync::atomic::AtomicUsize;
 use std::sync::Arc;
+use std::sync::atomic::AtomicUsize;
 
 use anyhow::Result;
 use bytes::Bytes;
diff --git a/mini-lsm-starter/src/mvcc/txn.rs b/mini-lsm-starter/src/mvcc/txn.rs
index 22adb68..e9ec40a 100644
--- a/mini-lsm-starter/src/mvcc/txn.rs
+++ b/mini-lsm-starter/src/mvcc/txn.rs
@@ -18,7 +18,7 @@
 use std::{
     collections::HashSet,
     ops::Bound,
-    sync::{atomic::AtomicBool, Arc},
+    sync::{Arc, atomic::AtomicBool},
 };
 
 use anyhow::Result;
@@ -28,7 +28,7 @@ use ouroboros::self_referencing;
 use parking_lot::Mutex;
 
 use crate::{
-    iterators::{two_merge_iterator::TwoMergeIterator, StorageIterator},
+    iterators::{StorageIterator, two_merge_iterator::TwoMergeIterator},
     lsm_iterator::{FusedIterator, LsmIterator},
     lsm_storage::LsmStorageInner,
 };
diff --git a/mini-lsm/src/compact.rs b/mini-lsm/src/compact.rs
index 3212b98..e531e11 100644
--- a/mini-lsm/src/compact.rs
+++ b/mini-lsm/src/compact.rs
@@ -28,10 +28,10 @@ pub use simple_leveled::{
 };
 pub use tiered::{TieredCompactionController, TieredCompactionOptions, TieredCompactionTask};
 
+use crate::iterators::StorageIterator;
 use crate::iterators::concat_iterator::SstConcatIterator;
 use crate::iterators::merge_iterator::MergeIterator;
 use crate::iterators::two_merge_iterator::TwoMergeIterator;
-use crate::iterators::StorageIterator;
 use crate::key::KeySlice;
 use crate::lsm_storage::{LsmStorageInner, LsmStorageState};
 use crate::manifest::ManifestRecord;
diff --git a/mini-lsm/src/iterators/merge_iterator.rs b/mini-lsm/src/iterators/merge_iterator.rs
index a4cc3c0..02361d7 100644
--- a/mini-lsm/src/iterators/merge_iterator.rs
+++ b/mini-lsm/src/iterators/merge_iterator.rs
@@ -13,8 +13,8 @@
 // limitations under the License.
 
 use std::cmp::{self};
-use std::collections::binary_heap::PeekMut;
 use std::collections::BinaryHeap;
+use std::collections::binary_heap::PeekMut;
 
 use anyhow::Result;
 
diff --git a/mini-lsm/src/iterators/two_merge_iterator.rs b/mini-lsm/src/iterators/two_merge_iterator.rs
index a85fd73..9ed5ffa 100644
--- a/mini-lsm/src/iterators/two_merge_iterator.rs
+++ b/mini-lsm/src/iterators/two_merge_iterator.rs
@@ -25,9 +25,9 @@ pub struct TwoMergeIterator<A: StorageIterator, B: StorageIterator> {
 }
 
 impl<
-        A: 'static + StorageIterator,
-        B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
-    > TwoMergeIterator<A, B>
+    A: 'static + StorageIterator,
+    B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
+> TwoMergeIterator<A, B>
 {
     fn choose_a(a: &A, b: &B) -> bool {
         if !a.is_valid() {
@@ -59,9 +59,9 @@ impl<
 }
 
 impl<
-        A: 'static + StorageIterator,
-        B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
-    > StorageIterator for TwoMergeIterator<A, B>
+    A: 'static + StorageIterator,
+    B: 'static + for<'a> StorageIterator<KeyType<'a> = A::KeyType<'a>>,
+> StorageIterator for TwoMergeIterator<A, B>
 {
     type KeyType<'a> = A::KeyType<'a>;
 
diff --git a/mini-lsm/src/lsm_iterator.rs b/mini-lsm/src/lsm_iterator.rs
index ba6fe99..8d2b341 100644
--- a/mini-lsm/src/lsm_iterator.rs
+++ b/mini-lsm/src/lsm_iterator.rs
@@ -14,13 +14,13 @@
 
 use std::ops::Bound;
 
-use anyhow::{bail, Result};
+use anyhow::{Result, bail};
 use bytes::Bytes;
 
+use crate::iterators::StorageIterator;
 use crate::iterators::concat_iterator::SstConcatIterator;
 use crate::iterators::merge_iterator::MergeIterator;
 use crate::iterators::two_merge_iterator::TwoMergeIterator;
-use crate::iterators::StorageIterator;
 use crate::mem_table::MemTableIterator;
 use crate::table::SsTableIterator;
 
diff --git a/mini-lsm/src/lsm_storage.rs b/mini-lsm/src/lsm_storage.rs
index fc611c7..e8930d3 100644
--- a/mini-lsm/src/lsm_storage.rs
+++ b/mini-lsm/src/lsm_storage.rs
@@ -16,8 +16,8 @@ use std::collections::{BTreeSet, HashMap};
 use std::fs::File;
 use std::ops::Bound;
 use std::path::{Path, PathBuf};
-use std::sync::atomic::AtomicUsize;
 use std::sync::Arc;
+use std::sync::atomic::AtomicUsize;
 
 use anyhow::{Context, Result};
 use bytes::Bytes;
@@ -28,14 +28,14 @@ use crate::compact::{
     CompactionController, CompactionOptions, LeveledCompactionController, LeveledCompactionOptions,
     SimpleLeveledCompactionController, SimpleLeveledCompactionOptions, TieredCompactionController,
 };
+use crate::iterators::StorageIterator;
 use crate::iterators::concat_iterator::SstConcatIterator;
 use crate::iterators::merge_iterator::MergeIterator;
 use crate::iterators::two_merge_iterator::TwoMergeIterator;
-use crate::iterators::StorageIterator;
 use crate::key::KeySlice;
 use crate::lsm_iterator::{FusedIterator, LsmIterator};
 use crate::manifest::{Manifest, ManifestRecord};
-use crate::mem_table::{map_bound, MemTable};
+use crate::mem_table::{MemTable, map_bound};
 use crate::mvcc::LsmMvccInner;
 use crate::table::{FileObject, SsTable, SsTableBuilder, SsTableIterator};
 
diff --git a/mini-lsm/src/manifest.rs b/mini-lsm/src/manifest.rs
index f13ff5f..0cad63f 100644
--- a/mini-lsm/src/manifest.rs
+++ b/mini-lsm/src/manifest.rs
@@ -17,7 +17,7 @@ use std::io::{Read, Write};
 use std::path::Path;
 use std::sync::Arc;
 
-use anyhow::{bail, Context, Result};
+use anyhow::{Context, Result, bail};
 use bytes::{Buf, BufMut};
 use parking_lot::{Mutex, MutexGuard};
 use serde::{Deserialize, Serialize};
diff --git a/mini-lsm/src/mem_table.rs b/mini-lsm/src/mem_table.rs
index 5c89150..3cb52c8 100644
--- a/mini-lsm/src/mem_table.rs
+++ b/mini-lsm/src/mem_table.rs
@@ -14,13 +14,13 @@
 
 use std::ops::Bound;
 use std::path::Path;
-use std::sync::atomic::AtomicUsize;
 use std::sync::Arc;
+use std::sync::atomic::AtomicUsize;
 
 use anyhow::Result;
 use bytes::Bytes;
-use crossbeam_skiplist::map::Entry;
 use crossbeam_skiplist::SkipMap;
+use crossbeam_skiplist::map::Entry;
 use ouroboros::self_referencing;
 
 use crate::iterators::StorageIterator;
diff --git a/mini-lsm/src/table.rs b/mini-lsm/src/table.rs
index 10afeae..0ed1459 100644
--- a/mini-lsm/src/table.rs
+++ b/mini-lsm/src/table.rs
@@ -20,7 +20,7 @@ use std::fs::File;
 use std::path::Path;
 use std::sync::Arc;
 
-use anyhow::{anyhow, bail, Result};
+use anyhow::{Result, anyhow, bail};
 pub use builder::SsTableBuilder;
 use bytes::{Buf, BufMut};
 pub use iterator::SsTableIterator;
diff --git a/mini-lsm/src/table/bloom.rs b/mini-lsm/src/table/bloom.rs
index ddeac13..0a0e5fc 100644
--- a/mini-lsm/src/table/bloom.rs
+++ b/mini-lsm/src/table/bloom.rs
@@ -14,7 +14,7 @@
 
 // Copyright 2021 TiKV Project Authors. Licensed under Apache-2.0.
 
-use anyhow::{bail, Result};
+use anyhow::{Result, bail};
 use bytes::{Buf, BufMut, Bytes, BytesMut};
 
 /// Implements a bloom filter
diff --git a/mini-lsm/src/tests/harness.rs b/mini-lsm/src/tests/harness.rs
index ba4a2eb..6bcf70e 100644
--- a/mini-lsm/src/tests/harness.rs
+++ b/mini-lsm/src/tests/harness.rs
@@ -1,3 +1,5 @@
+#![allow(dead_code)] // REMOVE THIS LINE once all modules are complete
+
 // Copyright (c) 2022-2025 Alex Chi Z
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -17,7 +19,7 @@ use std::{
     time::Duration,
 };
 
-use anyhow::{bail, Result};
+use anyhow::{Result, bail};
 use bytes::Bytes;
 
 use crate::{
@@ -25,7 +27,7 @@ use crate::{
         CompactionOptions, LeveledCompactionOptions, SimpleLeveledCompactionOptions,
         TieredCompactionOptions,
     },
-    iterators::{merge_iterator::MergeIterator, StorageIterator},
+    iterators::{StorageIterator, merge_iterator::MergeIterator},
     key::{KeySlice, TS_ENABLED},
     lsm_storage::{BlockCache, LsmStorageInner, LsmStorageState, MiniLsm},
     table::{SsTable, SsTableBuilder, SsTableIterator},
@@ -128,7 +130,6 @@ where
     assert!(!iter.is_valid());
 }
 
-#[allow(dead_code)]
 pub fn check_iter_result_by_key_and_ts<I>(iter: &mut I, expected: Vec<((Bytes, u64), Bytes)>)
 where
     I: for<'a> StorageIterator<KeyType<'a> = KeySlice<'a>>,
@@ -207,7 +208,6 @@ pub fn generate_sst(
     builder.build(id, block_cache, path.as_ref()).unwrap()
 }
 
-#[allow(dead_code)]
 pub fn generate_sst_with_ts(
     id: usize,
     path: impl AsRef<Path>,
@@ -290,7 +290,9 @@ pub fn compaction_bench(storage: Arc<MiniLsm>) {
 
     storage.dump_structure();
 
-    println!("This test case does not guarantee your compaction algorithm produces a LSM state as expected. It only does minimal checks on the size of the levels. Please use the compaction simulator to check if the compaction is correctly going on.");
+    println!(
+        "This test case does not guarantee your compaction algorithm produces a LSM state as expected. It only does minimal checks on the size of the levels. Please use the compaction simulator to check if the compaction is correctly going on."
+    );
 }
 
 pub fn check_compaction_ratio(storage: Arc<MiniLsm>) {
diff --git a/mini-lsm/src/tests/week1_day2.rs b/mini-lsm/src/tests/week1_day2.rs
index 6cb42e0..66cf07b 100644
--- a/mini-lsm/src/tests/week1_day2.rs
+++ b/mini-lsm/src/tests/week1_day2.rs
@@ -18,14 +18,14 @@ use bytes::Bytes;
 use tempfile::tempdir;
 
 use crate::{
-    iterators::{merge_iterator::MergeIterator, StorageIterator},
+    iterators::{StorageIterator, merge_iterator::MergeIterator},
     lsm_iterator::FusedIterator,
     lsm_storage::{LsmStorageInner, LsmStorageOptions},
     mem_table::MemTable,
     tests::harness::check_lsm_iter_result_by_key,
 };
 
-use super::harness::{check_iter_result_by_key, expect_iter_error, MockIterator};
+use super::harness::{MockIterator, check_iter_result_by_key, expect_iter_error};
 
 #[test]
 fn test_task1_memtable_iter() {
diff --git a/mini-lsm/src/tests/week1_day4.rs b/mini-lsm/src/tests/week1_day4.rs
index 7a82cf6..64b0ce8 100644
--- a/mini-lsm/src/tests/week1_day4.rs
+++ b/mini-lsm/src/tests/week1_day4.rs
@@ -15,7 +15,7 @@
 use std::sync::Arc;
 
 use bytes::Bytes;
-use tempfile::{tempdir, TempDir};
+use tempfile::{TempDir, tempdir};
 
 use crate::iterators::StorageIterator;
 use crate::key::{KeySlice, KeyVec};
diff --git a/mini-lsm/src/tests/week1_day5.rs b/mini-lsm/src/tests/week1_day5.rs
index fcd2233..9532e97 100644
--- a/mini-lsm/src/tests/week1_day5.rs
+++ b/mini-lsm/src/tests/week1_day5.rs
@@ -15,7 +15,7 @@
 use std::ops::Bound;
 use std::sync::Arc;
 
-use self::harness::{check_iter_result_by_key, MockIterator};
+use self::harness::{MockIterator, check_iter_result_by_key};
 use self::harness::{check_lsm_iter_result_by_key, generate_sst};
 use bytes::Bytes;
 use tempfile::tempdir;
diff --git a/mini-lsm/src/tests/week1_day7.rs b/mini-lsm/src/tests/week1_day7.rs
index b2b6c3c..24bc889 100644
--- a/mini-lsm/src/tests/week1_day7.rs
+++ b/mini-lsm/src/tests/week1_day7.rs
@@ -16,7 +16,7 @@ use tempfile::tempdir;
 
 use crate::{
     key::{KeySlice, TS_ENABLED},
-    table::{bloom::Bloom, FileObject, SsTable, SsTableBuilder},
+    table::{FileObject, SsTable, SsTableBuilder, bloom::Bloom},
 };
 
 fn key_of(idx: usize) -> Vec<u8> {
diff --git a/mini-lsm/src/tests/week2_day1.rs b/mini-lsm/src/tests/week2_day1.rs
index ee44175..3337392 100644
--- a/mini-lsm/src/tests/week2_day1.rs
+++ b/mini-lsm/src/tests/week2_day1.rs
@@ -21,7 +21,7 @@ use week2_day1::harness::construct_merge_iterator_over_storage;
 
 use super::*;
 use crate::{
-    iterators::{concat_iterator::SstConcatIterator, StorageIterator},
+    iterators::{StorageIterator, concat_iterator::SstConcatIterator},
     key::{KeySlice, TS_ENABLED},
     lsm_storage::{LsmStorageInner, LsmStorageOptions},
     table::{SsTable, SsTableBuilder},
diff --git a/mini-lsm/src/wal.rs b/mini-lsm/src/wal.rs
index 08f615c..2bd5812 100644
--- a/mini-lsm/src/wal.rs
+++ b/mini-lsm/src/wal.rs
@@ -18,7 +18,7 @@ use std::io::{BufWriter, Read, Write};
 use std::path::Path;
 use std::sync::Arc;
 
-use anyhow::{bail, Context, Result};
+use anyhow::{Context, Result, bail};
 use bytes::{Buf, BufMut, Bytes};
 use crossbeam_skiplist::SkipMap;
 use parking_lot::Mutex;
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index 5aaa880..fada57f 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -14,7 +14,7 @@
 
 use std::path::{Path, PathBuf};
 
-use anyhow::{anyhow, Result};
+use anyhow::{Result, anyhow};
 use clap::Parser;
 use console::style;
 use duct::cmd;