returns the acetype bit of a text value

def getAceTypeBit(self, t):
        '''
        returns the acetype bit of a text value
        '''
        try:
            return self.validAceTypes[t]['BITS']
        except KeyError:
            raise CommandExecutionError((
                'No ACE type "{0}".  It should be one of the following:  {1}'
                ).format(t, ', '.join(self.validAceTypes)))