FastAPI will use this `response_model` to:

-   Convert the output data to its type declaration.
-   Validate the data.
-   Add a JSON Schema for the response, in the OpenAPI _path operation_.
-   Will be used by the automatic documentation systems.

But most importantly:

-   Will limit the output data to that of the model. We'll see how that's important below.

{
    "header": {
        "status": 1,
        "mesage": "Success",
        "persian_message": "عملیات موفق"
    },
    "content": {
        "id": 1,
        "name": "Foo"
    }
}

class Folan(BaseModel):
    id: int
    name: str


@app.post("/folan/", response_model=Folan)
async def create_item(folan: Folan):
    return folan

def do_something(custom_var: MyCustomType[List[int]]):
    ...

import enum
from typing import Generic, TypeVar

from pydantic.generics import GenericModel
from pydantic import Field


T = TypeVar("T")


class ApiStatus(enum):
    SUCCESS = 1
    FAILURE = 0


class ApiResponseHeader(GenericModel, Generic[T]):
    """ Header type of APIResponseType"""
    status: int = Field(..., description=str(list(ApiStatus)))
    message: str = "Success"
    persian_message: str = "عملیات موفق"


class APIResponseType(GenericModel, Generic[T]):
    """
    an api response type for using as the api's router response_model
    """
    header: ApiResponseHeader
    content: T

class Folan(BaseModel):
    id: int
    name: str


@app.post("/folan/", response_model=APIResponseType[Folan])
async def create_item(folan: Folan):
    return folan

class PaginatedContent(GenericModel, Generic[T]):
    """ Content data type for lists with pagination"""
    data: T
    total_count: int = 0
    limit: int = 100
    offset: int = 0

class Folan(BaseModel):
    id: int
    name: str


@app.get(
    "/folan/",
    response_model=APIResponseType[PaginatedContent[List[Folan]]],
    )
async def read_folans(limit: int = None, skip: int = 0):
    return {
            "data": [Folan(name="first"), Folan(name="second")],
            "total_count": 10,
            "limit": limit,
            "offset": skip,
        }