//Append copy arr's k/v struct to m
Append copy arr's k/v struct to m
// Append copy arr ' s k / v struct to m
func (f F) Append(s F) {
	for k, v := range s {
		f[k] = v
	}
}
func ( f F ) Append ( s F ) { for k , v := range s { f [ k ] = v } }
Append copy arr's k/v struct to m
Append copy arr ' s k / v struct to m