code: def compiled_relationships(self):
          
  
          def get_column_args(column):
              tmp = []
              for arg_name, arg_val in column.items():
                  if arg_name not in ('name', 'type', 'reference', 'class'):
                      if arg_name in ('back_populates', ):
                          arg_val = "'{}'".format(arg_val)
                      tmp.append(ALCHEMY_TEMPLATES.column_arg.safe_substitute(arg_name=arg_name,
                                                                              arg_val=arg_val))
              return ", ".join(tmp)
  
          res = []
          for column in self.relationship_definitions:
              column_args = get_column_args(column)
              column_name = column.get('name')
              cls_name = column.get("class")
              res.append(
                  ALCHEMY_TEMPLATES.relationship.safe_substitute(column_name=column_name,
                                                                 column_args=column_args,
                                                                 class_name=cls_name))
          join_string = "\n" + self.tab
          return join_string.join(res)
docs: Returns compiled relationship definitions