code: def make_pre_authed_request(self, env, method=None, path=None, body=None,
                                  headers=None):
          
          if self.default_storage_policy:
              sp = self.default_storage_policy
              if headers:
                  headers.update({'X-Storage-Policy': sp})
              else:
                  headers = {'X-Storage-Policy': sp}
          subreq = swift.common.wsgi.make_pre_authed_request(
              env, method=method, path=path, body=body, headers=headers,
              agent=self.agent)
          subreq.environ['swift.source'] = self.swift_source
          return subreq
docs: Nearly the same as swift.common.wsgi.make_pre_authed_request
          except that this also always sets the 'swift.source' and user
          agent.
  
          Newer Swift code will support swift_source as a kwarg, but we
          do it this way so we don't have to have a newer Swift.
  
          Since we're doing this anyway, we may as well set the user
          agent too since we always do that.