code: def update(self, argv):
          
  
          if len(argv) == 0: 
              error("Command requires an index name", 2)
          name = argv[0]
  
          if name not in self.service.indexes:
              error("Index '%s' does not exist" % name, 2)
          index = self.service.indexes[name]
  
          # Read index metadata and construct command line parser rules that 
          # correspond to each editable field.
  
          # Request editable fields
          fields = self.service.indexes.itemmeta().fields.optional
  
          # Build parser rules
          rules = dict([(field, {'flags': ["--%s" % field]}) for field in fields])
  
          # Parse the argument vector
          opts = cmdline(argv, rules)
  
          # Execute the edit request
          index.update(**opts.kwargs)
docs: Update an index according to the given argument vector.