args.go
func (a *Args) Has(key string) bool {
	return hasArg(a.args, key)
}
func (a *Args) Has(key string) bool {
	return hasArg(a.args, key)
}
func ( a * Args ) Has ( key string ) bool { return hasArg ( a . args , key ) }
// Has returns true if the given key exists in Args.
Has returns true if the given key exists in Args .