'return a new selectable with the \'use_labels\' flag set to True.
This will result in column expressions being generated using labels
against their table name, such as "SELECT somecolumn AS
tablename_somecolumn". This allows selectables which contain multiple
FROM clauses to produce a unique set of column names regardless of
name conflicts among the individual FROM clauses.'

@_generative
def apply_labels(self):

    self.use_labels = True
