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

            [subcategories] => Array
                (
                    [0] => Array
                        (
                            [name] => ACT Math
                            [slug] => act-math
                            [id] => 1741
                        )

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

                    [2] => Array
                        (
                            [name] => Algebra 2
                            [slug] => algebra-2
                            [id] => 1726
                        )

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

                    [4] => Array
                        (
                            [name] => Prealgebra
                            [slug] => prealgebra
                            [id] => 1724
                        )

                    [5] => Array
                        (
                            [name] => Precalculus
                            [slug] => precalculus
                            [id] => 1728
                        )

                    [6] => Array
                        (
                            [name] => Probability
                            [slug] => probability
                            [id] => 1735
                        )

                    [7] => Array
                        (
                            [name] => Statistics
                            [slug] => statistics
                            [id] => 1736
                        )

                    [8] => Array
                        (
                            [name] => Trigonometry
                            [slug] => trigonometry
                            [id] => 1729
                        )

                )

        )

    [1785] => Array
        (
            [parent_category_id] => 1785
            [parent_category] => Array
                (
                    [id] => 1785
                    [slug] => music
                    [name] => Music
                )

            [subcategories] => Array
                (
                    [0] => Array
                        (
                            [name] => Ear Training
                            [slug] => ear-training
                            [id] => 1796
                        )

                    [1] => Array
                        (
                            [name] => Guitar
                            [slug] => guitar
                            [id] => 1788
                        )

                    [2] => Array
                        (
                            [name] => Music Production
                            [slug] => music-production
                            [id] => 1797
                        )

                    [3] => Array
                        (
                            [name] => Music Theory
                            [slug] => music-theory
                            [id] => 1787
                        )

                )

        )

)