Return a < b.  Computed by @total_ordering from (a <= b) and (a != b).

def _lt_from_le(self, other):
    """Return a < b.  Computed by @total_ordering from (a <= b) and (a != b)."""
    op_result = self.__le__(other)
    if op_result is NotImplemented:
        return NotImplemented
    return op_result and self != other