Moves copy into SSZ container

test_libs/pyspec/eth2spec/utils/ssz/ssz_typing.py

@@ -1,3 +1,4 @@
+import copy
 from types import GeneratorType
 from typing import (
     List,
@@ -151,6 +152,9 @@ class Container(object):
     def __hash__(self):
         return hash(self.hash_tree_root())
 
+    def copy(self):
+        return copy.deepcopy(self)
+
     @classmethod
     def get_fields_dict(cls):
         return dict(cls.__annotations__)