Is one string a scramble of another string (leetcode)

is_scramble.py

def is_scramble(s1: str, s2: str) -> bool:
    if len(s1) != len(s2):
        return False
    if len(s1) == 0 or s1 == s2:
        return True

    sorted_s1 = sorted(s1)
    sorted_s2 = sorted(s2)
    if sorted_s1 != sorted_s2:
        return False
    for i in range(1, len(s1)):
        if is_scramble(s1[:i], s2[:i]) and is_scramble(s1[i:], s2[i:]):
            return True
        rest = len(s2) - i
        if is_scramble(s1[:i], s2[rest:]) and is_scramble(s1[i:], s2[:rest]):
            return True
    return False


if __name__ == '__main__':
    assert is_scramble("gr", "rg")
    assert is_scramble("great", "rgeat")
    assert not is_scramble("abcde", "caebd")