human
I wrote the below code

    if ((parser.lower_bound is not None) or (parser.upper_bound is not None)):
        def Checker(value):
            if ((value is not None) and parser.IsOutsideBounds(value)):
                message = ('%s    is    not    %s' % (value, parser.syntactic_help))
                raise gflags_validators.Error(message)
            return True
        RegisterValidator(name, Checker, flag_values=flag_values)

What's a good function header?
 ... Here's a good function header?
assistant
#Here's a good function header.

def _RegisterBoundsValidatorIfNeeded(parser, name, flag_values):