class HttpResponseHeaders:
    """Commonly used response headers"""

    CACHE_CONTROL = 'cache-control'
    CONTENT_LENGTH = 'content-length'
    CONTENT_TYPE = 'content-type'
    DATE = 'date'
    EXPIRES = 'expires'
    LAST_MODIFIED = 'last-modified'
    LOCATION = 'location'
    SET_COOKIE = 'set-cookie'
