$output = concat(['1','2','3'],['4','5','6'],['7','8','9'])
validate_array($output)
if size($output) != 9 {
fail("${output} should have 9 elements.")
}
$output = concat(['1','2','3'],['4','5','6'],['7','8','9'])
validate_array($output)
if size($output) != 9 {
fail("${output} should have 9 elements.")
}