code: def _get_targets_by_declared_platform_with_placeholders(self, targets_by_platform):
      
  
      if not targets_by_platform:
        for platform in self._python_setup.platforms:
          targets_by_platform[platform] = ['(No target) Platform inherited from either the '
                                            '--platforms option or a pants.ini file.']
      return targets_by_platform
docs: Aggregates a dict that maps a platform string to a list of targets that specify the platform.
      If no targets have platforms arguments, return a dict containing platforms inherited from
      the PythonSetup object.
  
      :param tgts: a list of :class:`Target` objects.
      :returns: a dict mapping a platform string to a list of targets that specify the platform.