code: def _collapse_postconditions(base_postconditions: List[Contract], postconditions: List[Contract]) -> List[Contract]:
      
      return base_postconditions + postconditions
docs: Collapse function postconditions with the postconditions collected from the base classes.
  
      :param base_postconditions: postconditions collected from the base classes
      :param postconditions: postconditions of the function (before the collapse)
      :return: collapsed sequence of postconditions