Given a list of ordered integers with some of the numbers missing (and with possible duplicates), find the missing numbers.

missing_ints.py

def missing_ints(numbers):
    """Given a list of ordered integers with some of the
    numbers missing (and with possible duplicates), find 
    the missing numbers.
    """
    if not numbers:
        return []
    missing_numbers = [n for n in range(min(numbers), max(numbers))
                       if n not in numbers]
    return missing_numbers


if __name__ == '__main__':
    CASES = (
        ([1, 3, 3, 3, 5], [2, 4]),
        ([1, 2, 3, 4, 4, 7, 7], [5, 6]),
        ([8, 8, 10, 12, 13], [9, 11]),
        ([-5, -1, 2, 4], [-4, -3, -2, 0, 1, 3]),
        ([], []),
    )
    
    for list_numbers, expected in CASES:
        result = missing_ints(list_numbers)
        assert result == expected, f'{result} != {expected}'