You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: main.go
    path of file: ./repos/build-web-application-with-golang/pt-br/code/src/apps/ch.2.3/type_function
    
    the code of the file until where you have to start completion: // Código de exemplo do capítulo 2.3 de "Build W
    
func main() {
	slice := []int{1, 2, 3, 4, 5, 7}
	fmt.Println("slice = ", slice)
	odd := filter(slice, isOdd) // usa funções como valores
	fmt.Println("Odd elements of slice are: ", odd)
	even := filter(slice, isEven)
	fmt.Println("Even elements of slice are: ", even)
}