diff --git a/src/ethereum/arrow_glacier/fork_types.py b/src/ethereum/arrow_glacier/fork_types.py
index 9d16f83f1b..3a9fc1ac95 100644
--- a/src/ethereum/arrow_glacier/fork_types.py
+++ b/src/ethereum/arrow_glacier/fork_types.py
@@ -146,7 +146,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -219,7 +219,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/berlin/fork_types.py b/src/ethereum/berlin/fork_types.py
index 95d503b477..1b26066f74 100644
--- a/src/ethereum/berlin/fork_types.py
+++ b/src/ethereum/berlin/fork_types.py
@@ -118,7 +118,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -190,7 +190,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/byzantium/fork_types.py b/src/ethereum/byzantium/fork_types.py
index 842eff7b98..7a87cf3170 100644
--- a/src/ethereum/byzantium/fork_types.py
+++ b/src/ethereum/byzantium/fork_types.py
@@ -67,7 +67,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -139,7 +139,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/constantinople/fork_types.py b/src/ethereum/constantinople/fork_types.py
index 842eff7b98..7a87cf3170 100644
--- a/src/ethereum/constantinople/fork_types.py
+++ b/src/ethereum/constantinople/fork_types.py
@@ -67,7 +67,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -139,7 +139,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/dao_fork/fork_types.py b/src/ethereum/dao_fork/fork_types.py
index bbeae34e3c..c99625a43b 100644
--- a/src/ethereum/dao_fork/fork_types.py
+++ b/src/ethereum/dao_fork/fork_types.py
@@ -67,7 +67,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -139,7 +139,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/frontier/fork_types.py b/src/ethereum/frontier/fork_types.py
index df25f3b7be..5b71de6b61 100644
--- a/src/ethereum/frontier/fork_types.py
+++ b/src/ethereum/frontier/fork_types.py
@@ -66,7 +66,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -138,7 +138,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/gray_glacier/fork_types.py b/src/ethereum/gray_glacier/fork_types.py
index 9d16f83f1b..3a9fc1ac95 100644
--- a/src/ethereum/gray_glacier/fork_types.py
+++ b/src/ethereum/gray_glacier/fork_types.py
@@ -146,7 +146,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -219,7 +219,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/homestead/fork_types.py b/src/ethereum/homestead/fork_types.py
index bbeae34e3c..c99625a43b 100644
--- a/src/ethereum/homestead/fork_types.py
+++ b/src/ethereum/homestead/fork_types.py
@@ -67,7 +67,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -139,7 +139,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/istanbul/fork_types.py b/src/ethereum/istanbul/fork_types.py
index e356cde726..955d0c8bba 100644
--- a/src/ethereum/istanbul/fork_types.py
+++ b/src/ethereum/istanbul/fork_types.py
@@ -67,7 +67,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -139,7 +139,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/london/fork_types.py b/src/ethereum/london/fork_types.py
index 9d16f83f1b..3a9fc1ac95 100644
--- a/src/ethereum/london/fork_types.py
+++ b/src/ethereum/london/fork_types.py
@@ -146,7 +146,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -219,7 +219,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/muir_glacier/fork_types.py b/src/ethereum/muir_glacier/fork_types.py
index e356cde726..955d0c8bba 100644
--- a/src/ethereum/muir_glacier/fork_types.py
+++ b/src/ethereum/muir_glacier/fork_types.py
@@ -67,7 +67,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -139,7 +139,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/paris/fork_types.py b/src/ethereum/paris/fork_types.py
index d2c38d5ace..8a3a22366c 100644
--- a/src/ethereum/paris/fork_types.py
+++ b/src/ethereum/paris/fork_types.py
@@ -146,7 +146,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -219,7 +219,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/shanghai/fork_types.py b/src/ethereum/shanghai/fork_types.py
index c5861e3c0c..c0a35ebbb7 100644
--- a/src/ethereum/shanghai/fork_types.py
+++ b/src/ethereum/shanghai/fork_types.py
@@ -146,7 +146,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -234,7 +234,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/spurious_dragon/fork_types.py b/src/ethereum/spurious_dragon/fork_types.py
index bbeae34e3c..c99625a43b 100644
--- a/src/ethereum/spurious_dragon/fork_types.py
+++ b/src/ethereum/spurious_dragon/fork_types.py
@@ -67,7 +67,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -139,7 +139,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable
diff --git a/src/ethereum/tangerine_whistle/fork_types.py b/src/ethereum/tangerine_whistle/fork_types.py
index bbeae34e3c..c99625a43b 100644
--- a/src/ethereum/tangerine_whistle/fork_types.py
+++ b/src/ethereum/tangerine_whistle/fork_types.py
@@ -67,7 +67,7 @@ class Account:
 
     nonce: Uint
     balance: U256
-    code: bytes
+    code: Bytes
 
 
 EMPTY_ACCOUNT = Account(
@@ -139,7 +139,7 @@ class Log:
 
     address: Address
     topics: Tuple[Hash32, ...]
-    data: bytes
+    data: Bytes
 
 
 @slotted_freezable