def get_locations(tasks):

    """
    Get a list of unique locations from a set of tasks

    :param tasks: tasks from json.load(open('task.json'))
    :type tasks: list

    :return: unique list of locations, which will be used as a primary key to link everything together
    :rtype: list
    """

    output_set = []
    for task in tasks:
        lat = str(round(task['info']['latitude'], 8))
        lng = str(round(task['info']['longitude'], 8))
        year = str(task['info']['year'])
        location = lat + lng + '---' + year
        output_set.append(location)

    return list(set(output_set))