@classmethod
def strip_off_end(cls, s: str, suf: str):
    """
		Strips the full string `suf` from the end of `str`.
		See `Tools.strip_off` for more info.
		"""
    assert isinstance(suf, str), '{} is not a string'.format(suf)
    if s.endswith(suf):
        s = s[:-len(suf)]
    return s
