args.go
func (a *Args) GetUfloat(key string) (float64, error) {
	value := a.Peek(key)
	if len(value) == 0 {
		return -1, ErrNoArgValue
	}
	return ParseUfloat(value)
}
func (a *Args) GetUfloat(key string) (float64, error) {
	value := a.Peek(key)
	if len(value) == 0 {
		return -1, ErrNoArgValue
	}
	return ParseUfloat(value)
}
// GetUfloat returns ufloat value for the given key.