util.go
func convertOptions(q url.Values, pairs ...string) url.Values {
	n := make(url.Values)
	for k, v := range q {
		x := make([]string, len(v))
		for i, z := range v {
			for j := 0; j < len(pairs); j += 2 {
				if pairs[j] == z {
					z = pairs[j+1]
				}
			}
			x[i] = z
		}
		n[k] = x
	}

	return n
}
func convertOptions(q url.Values, pairs ...string) url.Values {
	n := make(url.Values)
	for k, v := range q {
		x := make([]string, len(v))
		for i, z := range v {
			for j := 0; j < len(pairs); j += 2 {
				if pairs[j] == z {
					z = pairs[j+1]
				}
			}
			x[i] = z
		}
		n[k] = x
	}

	return n
}
// convertOptions converts an option value based on name, value pairs.