def get_number_of_ratings(ratings):
    """Gets the total number of ratings represented by the given ratings
    object.

    Args:
        ratings: dict. A dict whose keys are '1', '2', '3', '4', '5' and whose
            values are nonnegative integers representing frequency counts.

    Returns:
        int. The total number of ratings given.
    """
    return sum(ratings.values())