Fix a syntax warning

Replaces 'is not' with != as we should be checking for equality, not identity.

Co-authored-by: Goksel Coban <[email protected]>

tinyman/v1/client.py

@@ -44,7 +44,7 @@ def prepare_app_optin_transactions(self, user_address=None):
         return txn_group
 
     def prepare_asset_optin_transactions(self, asset_id, user_address=None):
-        assert asset_id is not 0, "Cannot opt into ALGO"
+        assert asset_id != 0, "Cannot opt into ALGO"
         user_address = user_address or self.user_address
         suggested_params = self.algod.suggested_params()
         txn_group = prepare_asset_optin_transactions(