def parse_requested_expands(query_key, request):
    """
    Extracts the value of the expand query string parameter from a request.
    Supports comma separated lists.

    :param query_key: The name query string parameter.
    :param request: Request instance.
    :return: List of strings representing the values of the expand query string value.
    """

    requested_expands = []

    for key, val in request.params.items():
        if key == query_key:
            requested_expands += val.split(',')

    return requested_expands