docs: def remove_temporary_source(self):
          """Remove the source files from this requirement, if they are marked
          for deletion"""
          if self.is_bundle or os.path.exists(self.delete_marker_filename):
              logger.info('Removing source in %s' % self.source_dir)
              if self.source_dir:
                  rmtree(self.source_dir)
              self.source_dir = None
          if self._temp_build_dir and os.path.exists(self._temp_build_dir):
              rmtree(self._temp_build_dir)
          self._temp_build_dir = None