def get_valid_values(self, attr):
        """
        Get the legal arguments for the setter associated with *attr*.

        This is done by querying the docstring of the function *set_attr*
        for a line that begins with ACCEPTS:

        e.g., for a line linestyle, return
        "[ ``'-'`` | ``'--'`` | ``'-.'`` | ``':'`` | ``'steps'`` | ``'None'``
        ]"
        """

        name = "set_%s" % attr
        if not hasattr(self.o, name):
            raise AttributeError("%s has no function %s" % (self.o, name))
        func = getattr(self.o, name)

        docstring = func.__doc__
        if docstring is None:
            return "unknown"

        if docstring.startswith("alias for "):
            return None

        match = self._get_valid_values_regex.search(docstring)
        if match is not None:
            return match.group(1).replace("\n", " ")
        return "unknown"

    def get_valid_values(self, attr):
        """
        Get the legal arguments for the setter associated with *attr*.

        This is done by querying the docstring of the function *set_attr*
        for a line that begins with ACCEPTS:

        Eg., for a line linestyle, return
        [ '-' | '--' | '-.' | ':' | 'steps' | 'None' ]
        """

        name = 'set_%s'%attr
        if not hasattr(self.o, name):
            raise AttributeError('%s has no function %s'%(self.o,name))
        func = getattr(self.o, name)

        docstring = func.__doc__
        if docstring is None: return 'unknown'

        if docstring.startswith('alias for '):
            return None

        match = self._get_valid_values_regex.search(docstring)
        if match is not None:
            return match.group(1).replace('\n', ' ')
        return 'unknown'