Write a function named `contains`

that accepts two arrays of integers `$a1`

and `$a2`

as parameters and that returns a value indicating whether or not `$a2`

's sequence of elements appears
in `$a1`

(`true`

for yes, `false`

for no). The sequence of elements in `$a2`

may
appear anywhere in `$a1`

but must appear consecutively and in the same order.

For example, if variables called `$a1`

and `$a2`

store the following values:

$a1 = [1, 6, 2, 1, 4, 1, 2, 1, 8];
$a2 = [1, 2, 1];

Then the call of `contains($a1, $a2)`

should return `true`

because `$a2`

's sequence
of values `[1, 2, 1]`

is contained in `$a1`

starting at index `5`

. If `$a2`

had stored the values `[2, 1, 2]`

, the call of `contains($a1, $a2)`

would return `false`

because `$a1`

does not contain that sequence of values. Any two arrays with identical elements are considered to
contain each other, so a call such as `contains($a1, $a1)`

should return `true`

.

*Constraints:*

- You may assume that both arrays passed to your function will have lengths of at least 1.
- You may not modify either of the passed arrays.
- You may not use any
`String`

s to help you solve this problem, nor functions that
produce `String`

s.