go short variable declaration
Inside a function, the := short assignment statement can be used in place of
a var declaration with implicit type.
Outside a function, every statement begins with a keyword (var, func, and so on)
and so the := construct is not available.
package main
import "fmt"
func main() {
var i, j int = 1, 2
k := 3
c, python, java := true, false, "no!"
fmt.Println(i, j, k, c, python, java)
}