code: func Value(keyvals []interface{}, key interface{}) interface{} {
  	for i := 0; i < 2*(len(keyvals)/2); i += 2 {
  		if keyvals[i] == key {
  			return keyvals[i+1]
  		}
  	}
  	return nil
  }
docs: // Return a single value corresponding to key in keyvals