'check whether the input ospf vrf name is valid'

def is_valid_vrf_name(self):

    if ((len(self.vrf) > 31) or (len(self.vrf) < 1)):
        return False
    if (self.vrf.find('?') != (-1)):
        return False
    if (self.vrf.find('    ') != (-1)):
        return False
    return True
