def _determine_output(iteration) -> str:
    """Determine what the output of each iteration is based on its divisibility."""
    fizz = iteration % 3 == 0
    buzz = iteration % 5 == 0

    if fizz and buzz:
        output = 'FizzBuzz'
    elif fizz:
        output = 'Fizz'
    elif buzz:
        output = 'Buzz'
    else:
        output = str(iteration)

    return output