diff --git a/scripts/build_spec.py b/scripts/build_spec.py
index d67c0e5c6..99c5cd69d 100644
--- a/scripts/build_spec.py
+++ b/scripts/build_spec.py
@@ -130,11 +130,7 @@ def objects_to_spec(functions: Dict[str, str],
     new_type_definitions = (
         '\n\n'.join(
             [
-                f"class {key}({value}):\n"
-                f"    def __init__(self, _x: {value}) -> None:\n"
-                f"        ...\n"
-                if value.startswith("uint")
-                else f"class {key}({value}):\n    pass\n"
+                f"class {key}({value}):\n    pass\n"
                 for key, value in custom_types.items()
             ]
         )
diff --git a/test_libs/pyspec/eth2spec/utils/ssz/ssz_typing.py b/test_libs/pyspec/eth2spec/utils/ssz/ssz_typing.py
index 6079f2866..58e66ca68 100644
--- a/test_libs/pyspec/eth2spec/utils/ssz/ssz_typing.py
+++ b/test_libs/pyspec/eth2spec/utils/ssz/ssz_typing.py
@@ -34,7 +34,7 @@ class BasicValue(int, SSZValue, metaclass=BasicType):
 class Bool(BasicValue):  # can't subclass bool.
     byte_len = 1
 
-    def __new__(cls, value, *args, **kwargs):
+    def __new__(cls, value: int):  # int value, but can be any subclass of int (bool, Bit, Bool, etc...)
         if value < 0 or value > 1:
             raise ValueError(f"value {value} out of bounds for bit")
         return super().__new__(cls, value)
@@ -54,7 +54,7 @@ class Bit(Bool):
 
 class uint(BasicValue, metaclass=BasicType):
 
-    def __new__(cls, value, *args, **kwargs):
+    def __new__(cls, value: int):
         if value < 0:
             raise ValueError("unsigned types must not be negative")
         if cls.byte_len and value.bit_length() > (cls.byte_len << 3):