code: def register_archive_format(name, function, extra_args=None, description=''):
      
      if extra_args is None:
          extra_args = []
      if not isinstance(function, collections.Callable):
          raise TypeError('The %s object is not callable' % function)
      if not isinstance(extra_args, (tuple, list)):
          raise TypeError('extra_args needs to be a sequence')
      for element in extra_args:
          if not isinstance(element, (tuple, list)) or len(element) !=2:
              raise TypeError('extra_args elements are : (arg_name, value)')
  
      _ARCHIVE_FORMATS[name] = (function, extra_args, description)
docs: Registers an archive format.
  
      name is the name of the format. function is the callable that will be
      used to create archives. If provided, extra_args is a sequence of
      (name, value) tuples that will be passed as arguments to the callable.
      description can be provided to describe the format, and will be returned
      by the get_archive_formats() function.