code: func (j *Job) ArgFloat64(key string) float64 {
  	v, ok := j.Args[key]
  	if ok {
  		rVal := reflect.ValueOf(v)
  		if isIntKind(rVal) {
  			return float64(rVal.Int())
  		} else if isUintKind(rVal) {
  			return float64(rVal.Uint())
  		} else if isFloatKind(rVal) {
  			return rVal.Float()
  		}
  		j.argError = typecastError("float64", key, v)
  	} else {
  		j.argError = missingKeyError("float64", key)
  	}
  	return 0.0
  }
docs: // ArgFloat64 returns j.Args[key] typed to a float64. 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().