code: def lookup(tag, group=None):
      """
      :param tag: Integer tag number
      :param group: Which :py:data:`~PIL.TiffTags.TAGS_V2_GROUPS` to look in
  
      .. versionadded:: 8.3.0
  
      :returns: Taginfo namedtuple, From the ``TAGS_V2`` info if possible,
          otherwise just populating the value and name from ``TAGS``.
          If the tag is not recognized, "unknown" is returned for the name
  
      """
  
      if group is not None:
          info = (
              TAGS_V2_GROUPS[group].get(tag)
              if group in TAGS_V2_GROUPS
              else None
          )
      else:
          info = TAGS_V2.get(tag)
      return info or TagInfo(tag, TAGS.get(tag, "unknown"))
  
imports: from collections import namedtuple
label_desc: Use image node_id 1 for calling a global function with example usage: lookup(tag, group) and returns: unknown