def assert_exactly_one_true(bool_list):
    """This method asserts that only one value of the provided list is True.

    :param bool_list: List of booleans to check
    :return: True if only one value is True, False otherwise
    """
    assert isinstance(bool_list, list)
    counter = 0
    for item in bool_list:
        if item:
            counter += 1
    return counter == 1