declar type in class python code example

Example 1: python typing list of strings

from typing import List

def my_func(l: List[int]):
    pass

Example 2: typing generator python

# Iterator
def infinite_stream(start: int) -> Iterator[int]:
    while True:
        yield start
        start += 1

# Generator        
def infinite_stream(start: int) -> Generator[int, None, None]:
    while True:
        yield start
        start += 1