code: def morphs(self, name, index_name=None):
          
          self.unsigned_integer("%s_id" % name)
          self.string("%s_type" % name)
          self.index(["%s_id" % name, "%s_type" % name], index_name)
docs: Add the proper columns for a polymorphic table.
  
          :type name: str
  
          :type index_name: str