Adding decimal support for python client generation (#19203)

* Adding decimal to template for Python generator

* Rerunning the build steps

* Add tests for decimal serialization and deserialization.

* Move test to python not legacy pydantic sample

* readd old imports

---------

Co-authored-by: Adam <abolfik@pollyex.com>

samples/openapi3/client/petstore/python/tests/test_api_client.py

@@ -10,6 +10,7 @@ $ pytest
 """
 
 import unittest
+from decimal import Decimal
 from enum import Enum
 
 from dateutil.parser import parse
@@ -180,6 +181,11 @@ class ApiClientTests(unittest.TestCase):
         result = self.api_client.sanitize_for_serialization(data)
         self.assertEqual(result, "1997-07-16T19:20:30.450000+01:00")
 
+    def test_sanitize_for_serialization_decimal(self):
+        data = Decimal("1.0")
+        result = self.api_client.sanitize_for_serialization(data)
+        self.assertEquals(result, "1.0")
+
     def test_sanitize_for_serialization_list_enum(self):
         class EnumSerialization(int, Enum):
             NUMBER_0 = 0

samples/openapi3/client/petstore/python/tests/test_deserialization.py

@@ -14,6 +14,7 @@ import os
 import time
 import unittest
 import datetime
+from decimal import Decimal
 
 import pytest as pytest
 
@@ -130,6 +131,15 @@ class DeserializationTests(unittest.TestCase):
         deserialized = self.deserialize(response, "datetime", 'application/json')
         self.assertTrue(isinstance(deserialized, datetime.datetime))
 
+    def test_deserialize_decimal(self):
+        """ deserialize decimal """
+        data = 1.1
+        response = json.dumps(data)
+
+        deserialized = self.deserialize(response, "decimal", 'application/json')
+        self.assertTrue(isinstance(deserialized, Decimal))
+        self.assertEqual(deserialized, Decimal(1.1))
+
     def test_deserialize_pet(self):
         """ deserialize pet """
         data = {