import json


def get_tour(tours,tour_id,session):
    """
    Returns a tour including coordinates given a
    `tour_id` (position of the tour in `tours`).
    """

    tour = tours[tour_id]
    tour_url = tour["_links"]["coordinates"]["href"]
    headers = {"onlyprops": "true"}
    response = session.get(tour_url, headers=headers)
    tour_data = json.loads(response.text)

    tour['coordinates'] = tour_data['items']

    return tour