def get_file_mime_type(file_name):
    """ Returns mime-type of a file based on its file extension.
    :param file_name: str -> name of the file
    :return: str -> mime-type of the file
    """

    mim_type = {
        "png": "image/png",
        "jpeg": "image/jpeg",
        "jpg": "image/jpeg",
        "jfif": "image/jpeg",
        "css": "text/css",
        "js": "text/javascript",
        "ico": "image/vnd.microsoft.icon",
        "svg": "image/svg+xml",
        "gif": "image/gif"
    }

    file_ext = file_name[len(file_name) - file_name[::-1].find("."):].lower()

    try:
        return mim_type[file_ext]
    except KeyError:
        raise ValueError(f"Unknown file extension: '{file_ext}'. You can add this file extension to "
                         f"tools/production_env_setup.py - get_file_mime_type")