code: def modify_pool(arg, opts, shell_opts):
      
  
      res = Pool.list({ 'name': arg })
      if len(res) < 1:
          print("No pool with name '%s' found." % arg, file=sys.stderr)
          sys.exit(1)
  
      p = res[0]
  
      if 'name' in opts:
          p.name = opts['name']
      if 'description' in opts:
          p.description = opts['description']
      if 'default-type' in opts:
          p.default_type = opts['default-type']
      if 'ipv4_default_prefix_length' in opts:
          p.ipv4_default_prefix_length = opts['ipv4_default_prefix_length']
      if 'ipv6_default_prefix_length' in opts:
          p.ipv6_default_prefix_length = opts['ipv6_default_prefix_length']
      if 'tags' in opts:
          tags = list(csv.reader([opts.get('tags', '')], escapechar='\\'))[0]
          p.tags = {}
          for tag_name in tags:
              tag = Tag()
              tag.name = tag_name
              p.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
          p.avps[key] = value
  
  
      p.save()
  
      print("Pool '%s' saved." % p.name)
docs: Modify a pool with the options set in opts