code: func (j *Job) ArgBool(key string) bool {
  	v, ok := j.Args[key]
  	if ok {
  		typedV, ok := v.(bool)
  		if ok {
  			return typedV
  		}
  		j.argError = typecastError("bool", key, v)
  	} else {
  		j.argError = missingKeyError("bool", key)
  	}
  	return false
  }
docs: // ArgBool returns j.Args[key] typed to a bool. If the key is missing or of the wrong type, it sets an argument error
  // on the job. This function is meant to be used in the body of a job handling function while extracting arguments,
  // followed by a single call to j.ArgError().