code: func _float64f(v interface{}) (float64, bool) {
  
  	f, ok := _float64(v)
  	if ok {
  		return f, true
  	}
  
  	i, ok := _int64(v)
  	if ok {
  		return float64(i), true
  	}
  
  	s := _string(v)
  	f, err := strconv.ParseFloat(s, 64)
  	if err == nil {
  		return f, true
  	}
  
  	return 0, false
  }
docs: // _float64 converts an interface{} to a float64 iff its native type is
  // a float, integer or a string representing a number.