challenge activity 8.6.2:The Lock class of the preceding problem has a small problem. It does not support combinations that start with one or more zeroes. For example, a combination of 0042 can be opened by entering just 42. Solve this problem by choosing a different representation. Instead of an integer, use a string to hold the input. Once again, the configuration is hardwired. You will see in Section 8.6 how to change it.