code: func ApplyInputSourceValues(context *cli.Context, inputSourceContext InputSourceContext, flags []cli.Flag) error {
  	for _, f := range flags {
  		inputSourceExtendedFlag, isType := f.(FlagInputSourceExtension)
  		if isType {
  			err := inputSourceExtendedFlag.ApplyInputSourceValue(context, inputSourceContext)
  			if err != nil {
  				return err
  			}
  		}
  	}
  
  	return nil
  }
docs: // ApplyInputSourceValues iterates over all provided flags and
  // executes ApplyInputSourceValue on flags implementing the
  // FlagInputSourceExtension interface to initialize these flags
  // to an alternate input source.