callable_annotation.py

from collections.abc import Callable, Awaitable

# Function with callable parameter
def feeder(get_next_item: Callable[[], str]) -> None:
    ...  # Body

# Function with multiple callable parameters
def async_query(on_success: Callable[[int], None],
                on_error: Callable[[int, Exception], None]) -> None:
    ...  # Body

# Async function example
async def on_update(value: str) -> None:
    ...  # Body

callback: Callable[[str], Awaitable[None]] = on_update