Python range-function example definition

main.py

#!/usr/bin/env python3

from typing import Generator, Optional
from numbers import Real

def my_range(start: Real, stop: Optional[Real]=None, step: Real=1) -> Generator[Real, None, None]:
    """ An example definition of Python 3's range-class as a function """
    
    # If only one argument was provided, use that
    # argument as the goal and set start to 0
    if stop is None:
        start, stop = 0, start
    
    # Improves readability
    current = start
    
    # If start + n*step doesn't add up to exactly stop,
    # this fixes that problem
    stop += stop % step
    
    # This ensures that the range isn't infinite
    # by checking that start+step really approaches stop
    if abs(start-stop) <= abs(start+step-stop):
        raise StopIteration
    
    # Until the goal is reached, keep yielding the current value
    while current != stop:
        yield current
        current += step

if __name__ == '__main__':

    for num in my_range(10):
        print(num, end=' ')
    print()

    for num in my_range(1, 11):
        print(num, end=' ')
    print()

    for num in my_range(0, 99, 2):
        print(num, end=' ')
    print()