def write_if_different(filename, data):
    """Write `data` to `filename`, if the content of the file is different.

    Parameters
    ----------
    filename : str
        The file name to be written to.
    data : bytes
        The data to be written to `filename`.
    """

    assert isinstance(data, bytes)

    if os.path.exists(filename):
        with open(filename, 'rb') as fd:
            original_data = fd.read()
    else:
        original_data = None

    if original_data != data:
        with open(filename, 'wb') as fd:
            fd.write(data)
Write `data` to `filename`, if the content of the file is different.

    Parameters
    ----------
    filename : str
        The file name to be written to.
    data : bytes
        The data to be written to `filename`.