diff --git a/test_libs/pyspec/eth2spec/utils/ssz/ssz_impl.py b/test_libs/pyspec/eth2spec/utils/ssz/ssz_impl.py
index 46d842e16..c3cc579bd 100644
--- a/test_libs/pyspec/eth2spec/utils/ssz/ssz_impl.py
+++ b/test_libs/pyspec/eth2spec/utils/ssz/ssz_impl.py
@@ -8,11 +8,11 @@ BYTES_PER_LENGTH_OFFSET = 4
 
 
 def is_basic_type(typ):
-    return is_uint(typ) or typ == bool
+    return is_uint_type(typ) or is_bool_type(typ)
 
 
 def serialize_basic(value, typ):
-    if is_uint(typ):
+    if is_uint_type(typ):
         return value.to_bytes(uint_byte_size(typ), 'little')
     if is_bool_type(typ):
         if value:
@@ -24,11 +24,11 @@ def serialize_basic(value, typ):
 def is_fixed_size(typ):
     if is_basic_type(typ):
         return True
-    elif is_list_type(typ):
+    elif is_list_kind(typ):
         return False
-    elif is_vector_type(typ):
-        return is_fixed_size(read_vector_elem_typ(typ))
-    elif is_container_typ(typ):
+    elif is_vector_kind(typ):
+        return is_fixed_size(read_vector_elem_type(typ))
+    elif is_container_type(typ):
         return all(is_fixed_size(t) for t in typ.get_field_types())
     else:
         raise Exception("Type not supported: {}".format(typ))
@@ -38,9 +38,9 @@ def is_fixed_size(typ):
 def serialize(obj, typ):
     if is_basic_type(typ):
         return serialize_basic(obj, typ)
-    elif is_list_type(typ) or is_vector_type(typ):
-        return encode_series(obj, [read_elem_typ(typ)]*len(obj))
-    elif is_container_typ(typ):
+    elif is_list_kind(typ) or is_vector_kind(typ):
+        return encode_series(obj, [read_elem_type(typ)]*len(obj))
+    elif is_container_type(typ):
         return encode_series(obj.get_field_values(), typ.get_field_types())
     else:
         raise Exception("Type not supported: {}".format(typ))
@@ -103,15 +103,15 @@ def mix_in_length(root, length):
 def hash_tree_root(obj, typ):
     if is_basic_type(typ):
         return merkleize_chunks(chunkify(serialize_basic(obj, typ)))
-    elif is_list_type(typ) or is_vector_type(typ):
-        subtype = read_elem_typ(typ)
+    elif is_list_kind(typ) or is_vector_kind(typ):
+        subtype = read_elem_type(typ)
         if is_basic_type(subtype):
             leaves = chunkify(pack(obj, subtype))
         else:
             leaves = [hash_tree_root(elem, subtype) for elem in obj]
         leaf_root = merkleize_chunks(leaves)
         return mix_in_length(leaf_root, len(obj)) if is_list_type(typ) else leaf_root
-    elif is_container_typ(typ):
+    elif is_container_type(typ):
         leaves = [hash_tree_root(elem, subtyp) for elem, subtyp in obj.get_fields()]
         return merkleize_chunks(chunkify(b''.join(leaves)))
     else:
@@ -120,7 +120,7 @@ def hash_tree_root(obj, typ):
 
 @infer_input_type
 def signing_root(obj, typ):
-    assert is_container_typ(typ)
+    assert is_container_type(typ)
     leaves = [hash_tree_root(elem, subtyp) for elem, subtyp in obj.get_fields()[:-1]]
     return merkleize_chunks(chunkify(b''.join(leaves)))
 
diff --git a/test_libs/pyspec/eth2spec/utils/ssz/ssz_typing.py b/test_libs/pyspec/eth2spec/utils/ssz/ssz_typing.py
index 93a272c8c..d16c66abb 100644
--- a/test_libs/pyspec/eth2spec/utils/ssz/ssz_typing.py
+++ b/test_libs/pyspec/eth2spec/utils/ssz/ssz_typing.py
@@ -61,7 +61,7 @@ class uint256(uint):
         return super().__new__(cls, value)
 
 
-def is_uint(typ):
+def is_uint_type(typ):
     # All integers are uint in the scope of the spec here.
     # Since we default to uint64. Bounds can be checked elsewhere.
     return issubclass(typ, int)
@@ -380,29 +380,48 @@ def is_bool_type(typ):
     return issubclass(typ, bool)
 
 def is_list_type(typ):
+    """
+    Checks if the given type is a list.
+    """
+    return (hasattr(typ, '_name') and typ._name == 'List')
+
+def is_bytes_type(typ):
+    # Do not accept subclasses of bytes here, to avoid confusion with BytesN
+    return typ == bytes
+
+def is_list_kind(typ):
     """
     Checks if the given type is a kind of list. Can be bytes.
     """
-    return (hasattr(typ, '_name') and typ._name == 'List') or typ == bytes
+    return is_list_type(typ) or is_bytes_type(typ)
 
 def is_vector_type(typ):
+    """
+    Checks if the given type is a vector.
+    """
+    return issubclass(typ, Vector)
+
+def is_bytesn_type(typ):
+    return issubclass(typ, BytesN)
+
+def is_vector_kind(typ):
     """
     Checks if the given type is a kind of vector. Can be BytesN.
     """
-    return issubclass(typ, Vector) or issubclass(typ, BytesN)
+    return is_vector_type(typ) or is_bytesn_type(typ)
 
-def is_container_typ(typ):
+def is_container_type(typ):
     return issubclass(typ, Container)
 
-def read_list_elem_typ(list_typ: Type[List[T]]) -> T:
+def read_list_elem_type(list_typ: Type[List[T]]) -> T:
     if list_typ.__args__ is None or len(list_typ.__args__) != 1:
         raise TypeError("Supplied list-type is invalid, no element type found.")
     return list_typ.__args__[0]
 
-def read_vector_elem_typ(vector_typ: Type[Vector[T, L]]) -> T:
+def read_vector_elem_type(vector_typ: Type[Vector[T, L]]) -> T:
     return vector_typ.elem_type
 
-def read_elem_typ(typ):
+def read_elem_type(typ):
     if typ == bytes:
         return byte
     elif is_list_type(typ):