def find_commas(st):
    """
    Returns list of string
    finds commas in a string which are at the current depth
    for ex in following string only one comma is counted
    "{ { [ ] } }, [ [ ] ]"
    fn will return ["{ { [ ] } }" , "[ [ ] ]"]
    """
    ret_list = []
    cur,curly_count, square_count = 0,0,0
    for i in range(len(st)):
        if st[i] == '{': curly_count += 1
        elif st[i] == '}': curly_count -= 1
        elif st[i] == '[': square_count += 1
        elif st[i] == ']': square_count -= 1
        elif st[i] == ',':
            if curly_count == square_count == 0:
                ret_list.append(st[cur:i])
                cur = i + 1
    ret_list.append(st[cur:])
    return ret_list