PhpSpreadsheet/tests/data/CellGetRangeBoundaries.php

<?php

return [
    [
        [
            [
                'B',
                4,
            ],
            [
                'E',
                9,
            ],
        ],
        'B4:E9',
    ],
    [
        [
            [
                'B',
                4,
            ],
            [
                'B',
                4,
            ],
        ],
        'B4',
    ],
];