create an array of term children

<?php
    $termchildren_array = array();
    $i = 0;

    $term_bo_id = get_term_by('name', 'bo', $taxtype)->term_id;
    $term_ata_id = get_term_by('name', 'ata', $taxtype)->term_id;
    $term_gora_id = get_term_by('name', 'gora', $taxtype)->term_id;

    $termchildren = get_term_children($term_bo_id, $taxtype);
    foreach ($termchildren as $child) {
        $term = get_term_by('id', $child, $taxtype);
        $termchildren_array[$i] = $term->name;
        ++$i;
    }

    $termchildren = get_term_children($term_ata_id, $taxtype);
    foreach ($termchildren as $child) {
        $term = get_term_by('id', $child, $taxtype);
        $termchildren_array[$i] = $term->name;
        ++$i;
    }
    $termchildren = get_term_children($term_gora_id, $taxtype);
    foreach ($termchildren as $child) {
        $term = get_term_by('id', $child, $taxtype);
        $termchildren_array[$i] = $term->name;
        ++$i;
    }
?>