def _check_operator(self, operator):
        """ Check Set-Up

        This method checks algorithm operator against the expected parent
        classes

        Parameters
        ----------
        operator : str
            Algorithm operator to check

        """

        if not isinstance(operator, type(None)):
            tree = [obj.__name__ for obj in getmro(operator.__class__)]

            if not any([parent in tree for parent in self._op_parents]):
                warn('{0} does not inherit an operator '
                     'parent.'.format(str(operator.__class__)))
Check Set-Up

        This method checks algorithm operator against the expected parent
        classes

        Parameters
        ----------
        operator : str
            Algorithm operator to check