def check_stability_and_equivalence(
    src_contents: str,
    dst_contents: str,
    *,
    mode: Mode,
    lines: Collection[tuple[int, int]] = (),
) -> None:
    """Perform stability and equivalence checks.

    Raise AssertionError if source and destination contents are not
    equivalent, or if a second pass of the formatter would format the
    content differently.
    """
    assert_equivalent(src_contents, dst_contents)
    assert_stable(src_contents, dst_contents, mode=mode, lines=lines)
Perform stability and equivalence checks.

    Raise AssertionError if source and destination contents are not
    equivalent, or if a second pass of the formatter would format the
    content differently.
    
src/black/__init__.py