code: def remove_temporary_source(self):
          # type: () -> None
          
          if self.source_dir and os.path.exists(
                  os.path.join(self.source_dir, PIP_DELETE_MARKER_FILENAME)):
              logger.debug('Removing source in %s', self.source_dir)
              rmtree(self.source_dir)
          self.source_dir = None
          self._temp_build_dir.cleanup()
          self.build_env.cleanup()
docs: Remove the source files from this requirement, if they are marked
          for deletion