diff --git a/README.md b/README.md
index d988bb33c..13e997679 100644
--- a/README.md
+++ b/README.md
@@ -644,6 +644,8 @@ poetry run pytest test/<TEST_FILE> # for a single file
 poetry run pytest test/<TEST_FILE>::<TEST_CASE> # for a single test case
 ```
 
+In case of problems with `test_postman` test on Mac please see https://stackoverflow.com/a/52230415.
+
 ### Development - Check versioning consistency
 
 ```
diff --git a/starknet_devnet/__init__.py b/starknet_devnet/__init__.py
index 3e1b2cc3b..9f0e2eb87 100644
--- a/starknet_devnet/__init__.py
+++ b/starknet_devnet/__init__.py
@@ -2,13 +2,16 @@
 Contains the server implementation and its utility classes and functions.
 """
 import sys
+from copy import copy
 from starkware.crypto.signature.fast_pedersen_hash import pedersen_hash
+from starkware.starknet.services.api.contract_class import ContractClass
 from crypto_cpp_py.cpp_bindings import cpp_hash
 
 
 __version__ = "0.3.2"
 
 
+
 def patched_pedersen_hash(left: int, right: int) -> int:
     """
     Pedersen hash function written in c++
@@ -24,3 +27,14 @@ def patched_pedersen_hash(left: int, right: int) -> int:
     "pedersen_hash",
     patched_pedersen_hash,
 )
+
+
+# Deep copy of a ContractClass takes a lot of time, but it should never be mutated.
+def simpler_copy(self, memo):  # pylint: disable=unused-argument
+    """
+    A dummy implementation of ContractClass.__deepcopy__
+    """
+    return copy(self)
+
+
+setattr(ContractClass, "__deepcopy__", simpler_copy)