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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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