Python typing
From wikinotes
Type annotations in python.
Example
from typing import Dict, List, Tuple, Optional class Project: def add_user(user: User) -> Bool pass def set_active(status: bool=False) -> Bool: pass def update_metadata(data: List[Dict]) -> List[Dict]: pass def grade() -> Optional[str]: # nullable type pass
Common Types
dates/times
import datetime def foo() -> datetime.datetime: return datetime.datetime.now() def foo() -> datetime.date: return datetime.date.today()open file objects
from typing import IO # either bytes/str def foo() -> IO: return open('foo.txt', 'r') def foo() -> IO[bytes]: return open('foo.txt', 'rb') def foo() -> IO[str]: return open('foo.txt', 'r')context managers
@contextlib.contextmanager def foo() -> Iterator[str]: print('foo') yield 'bar' print('baz')