what is the use typing module in python code example

Example 1: specify return type python function

def greeting(name: str) -> str:
  return 'Hello, {}'.format(name)

Example 2: python typing module list

"""
typing.Tuple and typing.List are Generic types; this means you can specify what type their contents must be:
"""

def f(points: Tuple[float, float]):
    return map(do_stuff, points)