code: func commandUsage(method string) {
  	usage, err := btcjson.MethodUsageText(method)
  	if err != nil {
  		// This should never happen since the method was already checked
  		// before calling this function, but be safe.
  		fmt.Fprintln(os.Stderr, "Failed to obtain command usage:", err)
  		return
  	}
  
  	fmt.Fprintln(os.Stderr, "Usage:")
  	fmt.Fprintf(os.Stderr, "  %s\n", usage)
  }
docs: // commandUsage display the usage for a specific command.