@staticmethod
def _vlan_tag_check(literal):
    """
        Check if the VLAN tag literal is a range or not and returns start and end tag number.

        :param literal: (str) VLAN tag literal
        :return: start_vlan (str), end_vlan (str)
        """
    if '-' in literal:
        vlans = literal.strip('-')
        return vlans[0], vlans[1]
    else:
        return literal, literal
