def METHOD_NAME(a: dict, b: dict, message_start: str) -> None:
    """Assert that Directories ``a`` and ``b`` are the same.
    ``b`` is treated as the expected values that ``a`` shall abide by.
    Print helpful error with custom message start.
    """
    mismatch: list[str] = []
    for b_key, b_value in b.items():
        if b_key not in a:
            mismatch.append(f"Missing item {b_key}: {b_value}")
        elif b_value != a[b_key]:
            mismatch.append(f"For {b_key} got {a[b_key]}, expected {b_value}")
    for a_key, a_value in a.items():
        if a_key not in b:
            mismatch.append(f"Extraneous item {a_key}: {a_value}")
    mismatch_str = "\n".join(mismatch)
    assert len(mismatch) == 0, f"{message_start}\n{mismatch_str}"