import zipfile


def is_valid(resource, file):
    """Check if the content is a DOCX file."""

    if not zipfile.is_zipfile(file.name):
        resource["error"] = "Not a ZIP file."
        return False

    with zipfile.ZipFile(file.name, "r") as zip_ref:
        zip_contents = zip_ref.namelist()

        required_files = ["word/document.xml", "word/styles.xml"]

        if not all(file in zip_contents for file in required_files):
            resource["error"] = "That does not look like an DOCX file."
            return False

        return True