Consider this snippet:
var arr1 = [666]
var arr2 = [1,2,3]
arr1.append_array(arr2)
print(arr1)
It doesn't work. The compiler responds me:
Invalid call. Nonexistent function 'append_array' in base 'Array'.
But the reference states its existence and its importance.
What is going on, after all? What am I doing wrong?