def get_geo_coordinates(tweet):
    """
    Get the user's geo coordinates, if they are included in the payload
    (otherwise return None)

    Args:
        tweet (Tweet or dict): A Tweet object or dictionary

    Returns:
        dict: dictionary with the keys "latitude" and "longitude"
              or, if unavaiable, None

    Example:
        >>> from tweet_parser.getter_methods.tweet_geo import get_geo_coordinates
        >>> tweet_geo = {"geo": {"coordinates": [1,-1]}}
        >>> get_geo_coordinates(tweet_geo)
        {'latitude': 1, 'longitude': -1}

        >>> tweet_no_geo = {"geo": {}}
        >>> get_geo_coordinates(tweet_no_geo) #returns None
    """
    if "geo" in tweet:
        if tweet["geo"] is not None:
            if "coordinates" in tweet["geo"]:
                [lat, lon] = tweet["geo"]["coordinates"]
                return {"latitude": lat, "longitude": lon}
    return None