diff --git a/modules/openapi-generator/src/main/resources/python-flask/model.mustache b/modules/openapi-generator/src/main/resources/python-flask/model.mustache
index 4e7ecde8ef2..b9603345608 100644
--- a/modules/openapi-generator/src/main/resources/python-flask/model.mustache
+++ b/modules/openapi-generator/src/main/resources/python-flask/model.mustache
@@ -71,7 +71,7 @@ class {{classname}}(Model):
 
 {{/-first}}
     @property
-    def {{name}}(self):
+    def {{name}}(self) -> {{dataType}}:
         """Gets the {{name}} of this {{classname}}.
 
         {{#description}}
@@ -84,7 +84,7 @@ class {{classname}}(Model):
         return self._{{name}}
 
     @{{name}}.setter
-    def {{name}}(self, {{name}}):
+    def {{name}}(self, {{name}}: {{dataType}}):
         """Sets the {{name}} of this {{classname}}.
 
         {{#description}}
diff --git a/samples/server/petstore/python-flask/openapi_server/models/api_response.py b/samples/server/petstore/python-flask/openapi_server/models/api_response.py
index 87801d39e32..983e11cc4ea 100644
--- a/samples/server/petstore/python-flask/openapi_server/models/api_response.py
+++ b/samples/server/petstore/python-flask/openapi_server/models/api_response.py
@@ -50,7 +50,7 @@ class ApiResponse(Model):
         return util.deserialize_model(dikt, cls)
 
     @property
-    def code(self):
+    def code(self) -> int:
         """Gets the code of this ApiResponse.
 
 
@@ -60,7 +60,7 @@ class ApiResponse(Model):
         return self._code
 
     @code.setter
-    def code(self, code):
+    def code(self, code: int):
         """Sets the code of this ApiResponse.
 
 
@@ -71,7 +71,7 @@ class ApiResponse(Model):
         self._code = code
 
     @property
-    def type(self):
+    def type(self) -> str:
         """Gets the type of this ApiResponse.
 
 
@@ -81,7 +81,7 @@ class ApiResponse(Model):
         return self._type
 
     @type.setter
-    def type(self, type):
+    def type(self, type: str):
         """Sets the type of this ApiResponse.
 
 
@@ -92,7 +92,7 @@ class ApiResponse(Model):
         self._type = type
 
     @property
-    def message(self):
+    def message(self) -> str:
         """Gets the message of this ApiResponse.
 
 
@@ -102,7 +102,7 @@ class ApiResponse(Model):
         return self._message
 
     @message.setter
-    def message(self, message):
+    def message(self, message: str):
         """Sets the message of this ApiResponse.
 
 
diff --git a/samples/server/petstore/python-flask/openapi_server/models/category.py b/samples/server/petstore/python-flask/openapi_server/models/category.py
index 222a30f6f28..4bdec5b25c4 100644
--- a/samples/server/petstore/python-flask/openapi_server/models/category.py
+++ b/samples/server/petstore/python-flask/openapi_server/models/category.py
@@ -45,7 +45,7 @@ class Category(Model):
         return util.deserialize_model(dikt, cls)
 
     @property
-    def id(self):
+    def id(self) -> int:
         """Gets the id of this Category.
 
 
@@ -55,7 +55,7 @@ class Category(Model):
         return self._id
 
     @id.setter
-    def id(self, id):
+    def id(self, id: int):
         """Sets the id of this Category.
 
 
@@ -66,7 +66,7 @@ class Category(Model):
         self._id = id
 
     @property
-    def name(self):
+    def name(self) -> str:
         """Gets the name of this Category.
 
 
@@ -76,7 +76,7 @@ class Category(Model):
         return self._name
 
     @name.setter
-    def name(self, name):
+    def name(self, name: str):
         """Sets the name of this Category.
 
 
diff --git a/samples/server/petstore/python-flask/openapi_server/models/order.py b/samples/server/petstore/python-flask/openapi_server/models/order.py
index b0df0613ccc..1fdf0cb3b79 100644
--- a/samples/server/petstore/python-flask/openapi_server/models/order.py
+++ b/samples/server/petstore/python-flask/openapi_server/models/order.py
@@ -65,7 +65,7 @@ class Order(Model):
         return util.deserialize_model(dikt, cls)
 
     @property
-    def id(self):
+    def id(self) -> int:
         """Gets the id of this Order.
 
 
@@ -75,7 +75,7 @@ class Order(Model):
         return self._id
 
     @id.setter
-    def id(self, id):
+    def id(self, id: int):
         """Sets the id of this Order.
 
 
@@ -86,7 +86,7 @@ class Order(Model):
         self._id = id
 
     @property
-    def pet_id(self):
+    def pet_id(self) -> int:
         """Gets the pet_id of this Order.
 
 
@@ -96,7 +96,7 @@ class Order(Model):
         return self._pet_id
 
     @pet_id.setter
-    def pet_id(self, pet_id):
+    def pet_id(self, pet_id: int):
         """Sets the pet_id of this Order.
 
 
@@ -107,7 +107,7 @@ class Order(Model):
         self._pet_id = pet_id
 
     @property
-    def quantity(self):
+    def quantity(self) -> int:
         """Gets the quantity of this Order.
 
 
@@ -117,7 +117,7 @@ class Order(Model):
         return self._quantity
 
     @quantity.setter
-    def quantity(self, quantity):
+    def quantity(self, quantity: int):
         """Sets the quantity of this Order.
 
 
@@ -128,7 +128,7 @@ class Order(Model):
         self._quantity = quantity
 
     @property
-    def ship_date(self):
+    def ship_date(self) -> datetime:
         """Gets the ship_date of this Order.
 
 
@@ -138,7 +138,7 @@ class Order(Model):
         return self._ship_date
 
     @ship_date.setter
-    def ship_date(self, ship_date):
+    def ship_date(self, ship_date: datetime):
         """Sets the ship_date of this Order.
 
 
@@ -149,7 +149,7 @@ class Order(Model):
         self._ship_date = ship_date
 
     @property
-    def status(self):
+    def status(self) -> str:
         """Gets the status of this Order.
 
         Order Status  # noqa: E501
@@ -160,7 +160,7 @@ class Order(Model):
         return self._status
 
     @status.setter
-    def status(self, status):
+    def status(self, status: str):
         """Sets the status of this Order.
 
         Order Status  # noqa: E501
@@ -178,7 +178,7 @@ class Order(Model):
         self._status = status
 
     @property
-    def complete(self):
+    def complete(self) -> bool:
         """Gets the complete of this Order.
 
 
@@ -188,7 +188,7 @@ class Order(Model):
         return self._complete
 
     @complete.setter
-    def complete(self, complete):
+    def complete(self, complete: bool):
         """Sets the complete of this Order.
 
 
diff --git a/samples/server/petstore/python-flask/openapi_server/models/pet.py b/samples/server/petstore/python-flask/openapi_server/models/pet.py
index 57cbb673879..b460a10303e 100644
--- a/samples/server/petstore/python-flask/openapi_server/models/pet.py
+++ b/samples/server/petstore/python-flask/openapi_server/models/pet.py
@@ -69,7 +69,7 @@ class Pet(Model):
         return util.deserialize_model(dikt, cls)
 
     @property
-    def id(self):
+    def id(self) -> int:
         """Gets the id of this Pet.
 
 
@@ -79,7 +79,7 @@ class Pet(Model):
         return self._id
 
     @id.setter
-    def id(self, id):
+    def id(self, id: int):
         """Sets the id of this Pet.
 
 
@@ -90,7 +90,7 @@ class Pet(Model):
         self._id = id
 
     @property
-    def category(self):
+    def category(self) -> Category:
         """Gets the category of this Pet.
 
 
@@ -100,7 +100,7 @@ class Pet(Model):
         return self._category
 
     @category.setter
-    def category(self, category):
+    def category(self, category: Category):
         """Sets the category of this Pet.
 
 
@@ -111,7 +111,7 @@ class Pet(Model):
         self._category = category
 
     @property
-    def name(self):
+    def name(self) -> str:
         """Gets the name of this Pet.
 
 
@@ -121,7 +121,7 @@ class Pet(Model):
         return self._name
 
     @name.setter
-    def name(self, name):
+    def name(self, name: str):
         """Sets the name of this Pet.
 
 
@@ -134,7 +134,7 @@ class Pet(Model):
         self._name = name
 
     @property
-    def photo_urls(self):
+    def photo_urls(self) -> List[str]:
         """Gets the photo_urls of this Pet.
 
 
@@ -144,7 +144,7 @@ class Pet(Model):
         return self._photo_urls
 
     @photo_urls.setter
-    def photo_urls(self, photo_urls):
+    def photo_urls(self, photo_urls: List[str]):
         """Sets the photo_urls of this Pet.
 
 
@@ -157,7 +157,7 @@ class Pet(Model):
         self._photo_urls = photo_urls
 
     @property
-    def tags(self):
+    def tags(self) -> List[Tag]:
         """Gets the tags of this Pet.
 
 
@@ -167,7 +167,7 @@ class Pet(Model):
         return self._tags
 
     @tags.setter
-    def tags(self, tags):
+    def tags(self, tags: List[Tag]):
         """Sets the tags of this Pet.
 
 
@@ -178,7 +178,7 @@ class Pet(Model):
         self._tags = tags
 
     @property
-    def status(self):
+    def status(self) -> str:
         """Gets the status of this Pet.
 
         pet status in the store  # noqa: E501
@@ -189,7 +189,7 @@ class Pet(Model):
         return self._status
 
     @status.setter
-    def status(self, status):
+    def status(self, status: str):
         """Sets the status of this Pet.
 
         pet status in the store  # noqa: E501
diff --git a/samples/server/petstore/python-flask/openapi_server/models/tag.py b/samples/server/petstore/python-flask/openapi_server/models/tag.py
index 1088ad71654..2a38c9ee02a 100644
--- a/samples/server/petstore/python-flask/openapi_server/models/tag.py
+++ b/samples/server/petstore/python-flask/openapi_server/models/tag.py
@@ -45,7 +45,7 @@ class Tag(Model):
         return util.deserialize_model(dikt, cls)
 
     @property
-    def id(self):
+    def id(self) -> int:
         """Gets the id of this Tag.
 
 
@@ -55,7 +55,7 @@ class Tag(Model):
         return self._id
 
     @id.setter
-    def id(self, id):
+    def id(self, id: int):
         """Sets the id of this Tag.
 
 
@@ -66,7 +66,7 @@ class Tag(Model):
         self._id = id
 
     @property
-    def name(self):
+    def name(self) -> str:
         """Gets the name of this Tag.
 
 
@@ -76,7 +76,7 @@ class Tag(Model):
         return self._name
 
     @name.setter
-    def name(self, name):
+    def name(self, name: str):
         """Sets the name of this Tag.
 
 
diff --git a/samples/server/petstore/python-flask/openapi_server/models/user.py b/samples/server/petstore/python-flask/openapi_server/models/user.py
index e8e31169954..868b4c85b94 100644
--- a/samples/server/petstore/python-flask/openapi_server/models/user.py
+++ b/samples/server/petstore/python-flask/openapi_server/models/user.py
@@ -75,7 +75,7 @@ class User(Model):
         return util.deserialize_model(dikt, cls)
 
     @property
-    def id(self):
+    def id(self) -> int:
         """Gets the id of this User.
 
 
@@ -85,7 +85,7 @@ class User(Model):
         return self._id
 
     @id.setter
-    def id(self, id):
+    def id(self, id: int):
         """Sets the id of this User.
 
 
@@ -96,7 +96,7 @@ class User(Model):
         self._id = id
 
     @property
-    def username(self):
+    def username(self) -> str:
         """Gets the username of this User.
 
 
@@ -106,7 +106,7 @@ class User(Model):
         return self._username
 
     @username.setter
-    def username(self, username):
+    def username(self, username: str):
         """Sets the username of this User.
 
 
@@ -117,7 +117,7 @@ class User(Model):
         self._username = username
 
     @property
-    def first_name(self):
+    def first_name(self) -> str:
         """Gets the first_name of this User.
 
 
@@ -127,7 +127,7 @@ class User(Model):
         return self._first_name
 
     @first_name.setter
-    def first_name(self, first_name):
+    def first_name(self, first_name: str):
         """Sets the first_name of this User.
 
 
@@ -138,7 +138,7 @@ class User(Model):
         self._first_name = first_name
 
     @property
-    def last_name(self):
+    def last_name(self) -> str:
         """Gets the last_name of this User.
 
 
@@ -148,7 +148,7 @@ class User(Model):
         return self._last_name
 
     @last_name.setter
-    def last_name(self, last_name):
+    def last_name(self, last_name: str):
         """Sets the last_name of this User.
 
 
@@ -159,7 +159,7 @@ class User(Model):
         self._last_name = last_name
 
     @property
-    def email(self):
+    def email(self) -> str:
         """Gets the email of this User.
 
 
@@ -169,7 +169,7 @@ class User(Model):
         return self._email
 
     @email.setter
-    def email(self, email):
+    def email(self, email: str):
         """Sets the email of this User.
 
 
@@ -180,7 +180,7 @@ class User(Model):
         self._email = email
 
     @property
-    def password(self):
+    def password(self) -> str:
         """Gets the password of this User.
 
 
@@ -190,7 +190,7 @@ class User(Model):
         return self._password
 
     @password.setter
-    def password(self, password):
+    def password(self, password: str):
         """Sets the password of this User.
 
 
@@ -201,7 +201,7 @@ class User(Model):
         self._password = password
 
     @property
-    def phone(self):
+    def phone(self) -> str:
         """Gets the phone of this User.
 
 
@@ -211,7 +211,7 @@ class User(Model):
         return self._phone
 
     @phone.setter
-    def phone(self, phone):
+    def phone(self, phone: str):
         """Sets the phone of this User.
 
 
@@ -222,7 +222,7 @@ class User(Model):
         self._phone = phone
 
     @property
-    def user_status(self):
+    def user_status(self) -> int:
         """Gets the user_status of this User.
 
         User Status  # noqa: E501
@@ -233,7 +233,7 @@ class User(Model):
         return self._user_status
 
     @user_status.setter
-    def user_status(self, user_status):
+    def user_status(self, user_status: int):
         """Sets the user_status of this User.
 
         User Status  # noqa: E501