Unknown unit type: %s

Raise code

                    val += self.UNITS[lower] * value
                    default_unit = lower
                elif lower in self.LALIAS:
                    u = self.LALIAS[lower]
                    val += self.UNITS[u] * value
                    default_unit = u
                else:
                    raise AttributeError('Unknown unit type: %s' % unit)
        return val, default_unit

    @classmethod
    def unit_attname(cls, unit_str):
        """
        Retrieve the unit attribute name for the given unit string.
        For example, if the given unit string is 'metre', return 'm'. """