Array
(
    [1723] => Array
        (
            [parent_category_id] => 1723
            [parent_category] => Array
                (
                    [id] => 1723
                    [slug] => math
                    [name] => Math
                )

            [subcategories] => Array
                (
                    [0] => Array
                        (
                            [name] => Algebra 1
                            [slug] => algebra-1
                            [id] => 1725
                        )

                    [1] => Array
                        (
                            [name] => Geometry
                            [slug] => geometry
                            [id] => 1727
                        )

                )

        )

    [1744] => Array
        (
            [parent_category_id] => 1744
            [parent_category] => Array
                (
                    [id] => 1744
                    [slug] => science
                    [name] => Science
                )

            [subcategories] => Array
                (
                    [0] => Array
                        (
                            [name] => Biochemistry
                            [slug] => biochemistry
                            [id] => 1751
                        )

                    [1] => Array
                        (
                            [name] => Biology
                            [slug] => biology
                            [id] => 1746
                        )

                    [2] => Array
                        (
                            [name] => Genetics
                            [slug] => genetics
                            [id] => 1753
                        )

                    [3] => Array
                        (
                            [name] => Physics
                            [slug] => physics
                            [id] => 1748
                        )

                )

        )

)