docs: def _local_list_files(self, args):
          '''
          List files for a package file
          '''
          if len(args) < 2:
              raise SPMInvocationError('A package filename must be specified')
  
          pkg_file = args[1]
          if not os.path.exists(pkg_file):
              raise SPMPackageError('Package file {0} not found'.format(pkg_file))
          formula_tar = tarfile.open(pkg_file, 'r:bz2')
          pkg_files = formula_tar.getmembers()
  
          for member in pkg_files:
              self.ui.status(member.name)