def cutprefix(s, prefix):
    """ Strip a `prefix` from the front of `s`.
      Return the suffix if `.startswith(prefix)`, else `s`.

      Example:

          >>> abc_def = 'abc.def'
          >>> cutprefix(abc_def, 'abc.')
          'def'
          >>> cutprefix(abc_def, 'zzz.')
          'abc.def'
          >>> cutprefix(abc_def, '.zzz') is abc_def
          True
  """
    if prefix and s.startswith(prefix):
        return s[len(prefix):]
    return s
