base_model_serialization.py

from pydantic import BaseModel


class GitlabUser(BaseModel):
    id: int
    username: str


class GitlabMr(BaseModel):
    id: int
    squash: bool
    web_url: str
    title: str
    author: GitlabUser


mr = GitlabMr(
    id=1,
    squash=True,
    web_url="http://foo",
    title="title",
    author=GitlabUser(id=42, username="Joe"),
)
json_str = mr.json()
print(json_str)