Before: Array
(
    [USA] => Array
        (
        )

    [Canada] => Array
        (
        )

)
<br>States: Array
(
    [CA] => California
    [OR] => Oregon
)
<br>Providences: Array
(
    [BC] => British Columbia
)
<br>After: Array
(
    [USA] => Array
        (
            [CA] => California
            [OR] => Oregon
        )

    [Canada] => Array
        (
            [BC] => British Columbia
        )

)