def METHOD_NAME(file_name: str, file: typing.IO, owner: User, mime_type: str) -> None:
    """Simple validator that denies all files. Separate for HTML since .html and .htm are both
    common suffixes for text/html files."""
    raise FileValidationError(
        _('File "{file_name}": HTML upload denied by site security policy').format(file_name=file_name)
    )