The use of else or elif becomes redundant and can be dropped if the last statement under the leading if / elif block is a break statement. In the case of an elif after break, it can be written as a separate if block. For else blocks after break, the statements can be shifted out of else. Please refer to the examples below for reference.

Refactoring the code this way can improve code-readability and make it easier to maintain.

Bad practice

def changing_denominators(p, q):
    while True:
        if q == 0:
            break
        else:
            print(p/q)
            q = q - 1

Preferred:

def changing_denominators(p, q):
    while True:
        if q == 0:
            break

        print(p/q)
        q = q - 1