code: def _get_aliased_pivot_columns(self):
          
          defaults = [self._foreign_key, self._other_key]
  
          columns = []
  
          for column in defaults + self._pivot_columns:
              value = '%s.%s AS pivot_%s' % (self._table, column, column)
              if value not in columns:
                  columns.append('%s.%s AS pivot_%s' % (self._table, column, column))
  
          return columns
docs: Get the pivot columns for the relation.
  
          :rtype: list