Fix problem in sanitize_for_serialization for Python (pydantic type SecretStr ) BUG#16086 (2nd pull) (#18023)

* fix-for-bug-16086

* add to_dict alternative

* fix assertEqual

* remove extra blank line + test_model Argument SecretStr set

* update samples / remove extra blank line

* restore sanitize test for serialization with different data types

* remove empty line in api_client.mustache

* remove 2nd empty line in api_client.mustache

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

@@ -8,7 +8,7 @@ import os
 import time
 import unittest
 
-from pydantic import ValidationError
+from pydantic import ValidationError, SecretStr, BaseModel, StrictStr, Field
 import pytest
 
 import petstore_api
@@ -407,9 +407,17 @@ class ModelTests(unittest.TestCase):
         a.pattern_with_digits_and_delimiter = "image_123"
         self.assertEqual(a.pattern_with_digits_and_delimiter, "image_123")
 
-        # test sanitize for serializaation with SecretStr (format: password)
+        # test sanitize for serialization with different data types
         self.assertEquals(petstore_api.ApiClient().sanitize_for_serialization(a), {'byte': b'string', 'date': '2013-09-17', 'number': 123.45, 'password': 'testing09876', 'pattern_with_digits_and_delimiter': 'image_123'})
 
+        # test sanitize for serialization with SecretStr (format: password)
+        class LoginTest(BaseModel):
+            username: StrictStr = Field(min_length=2, strict=True, max_length=64)
+            password: SecretStr
+        
+        l = LoginTest(username="admin", password=SecretStr("testing09876"))
+        self.assertEqual(petstore_api.ApiClient().sanitize_for_serialization(l), {'username': "admin", 'password': "testing09876"})
+
     def test_inline_enum_validator(self):
         self.pet = petstore_api.Pet(name="test name", photoUrls=["string"])
         self.pet.id = 1