Stop using deprecated web3.py interface (#1759)

* Refactor contract function call to support web3.py v5.0.0. (backwards compatible with v4)

python-packages/order_utils/src/zero_ex/order_utils/__init__.py

@@ -428,9 +428,9 @@ def is_valid_signature(
     )
     try:
         return (
-            contract.call().isValidSignature(
+            contract.functions.isValidSignature(
                 data, to_checksum_address(signer_address), signature
-            ),
+            ).call(),
             "",
         )
     except web3.exceptions.BadFunctionCallOutput as exception:

python-packages/order_utils/stubs/web3/utils/datatypes.pyi

@@ -1,3 +1,12 @@
-class Contract:
-    def call(self): ...
+from typing import Callable
+
+
+class ContractFunctions:
+    def __getattr__(self, function_name) -> Callable:
+        ...
+    ...
+
+
+class Contract:
+    functions: ContractFunctions
     ...