code: def with_labels(self, selectable, base=None, **mapper_args):
          
  
          # TODO give meaningful aliases
          return self.map(
                      expression._clause_element_as_expr(selectable).
                              select(use_labels=True).
                              alias('foo'), base=base, **mapper_args)
docs: Map a selectable directly, wrapping the 
          selectable in a subquery with labels.
  
          The class and its mapping are not cached and will
          be discarded once dereferenced (as of 0.6.6).
  
          :param selectable: an :func:`.expression.select` construct.
          :param base: a Python class which will be used as the
            base for the mapped class. If ``None``, the "base"
            argument specified by this :class:`.SQLSoup`
            instance's constructor will be used, which defaults to
            ``object``.
          :param mapper_args: Dictionary of arguments which will
            be passed directly to :func:`.orm.mapper`.