code: def modify_vrf(arg, opts, shell_opts):
      
  
      res = VRF.list({ 'rt': arg })
      if len(res) < 1:
          print("VRF with [RT: %s] not found." % arg, file=sys.stderr)
          sys.exit(1)
  
      v = res[0]
  
      if 'rt' in opts:
          v.rt = opts['rt']
      if 'name' in opts:
          v.name = opts['name']
      if 'description' in opts:
          v.description = opts['description']
      if 'tags' in opts:
          tags = list(csv.reader([opts.get('tags', '')], escapechar='\\'))[0]
          v.tags = {}
          for tag_name in tags:
              tag = Tag()
              tag.name = tag_name
              v.tags[tag_name] = tag
  
      for avp in opts.get('extra-attribute', []):
          try:
              key, value = avp.split('=', 1)
          except ValueError:
              print("ERROR: Incorrect extra-attribute: %s. Accepted form: 'key=value'\n" % avp, file=sys.stderr)
              return
          v.avps[key] = value
  
      v.save()
  
      print("%s saved." % vrf_format(v))
docs: Modify a VRF with the options set in opts