def clean_name(s: str, white_space_to: str, snake_case: bool) -> str:
    """
    >>> clean_name('abc', '', False)
    'Abc'
    >>> clean_name('ab c', '_', True)
    'ab_c'
    """
    s = s.replace(' ', white_space_to)
    if snake_case:
        return s.lower()
    return s[0:1].upper() + s[1:]