Consider the following problem. A babysitter is logging all the earnings they get for children they care for. You must write source code for classes that can be used in a calculator program to help this babysitter to tally their total earnings. The classes should be designed as follows:

A BabySitter has a listing of children they care for called children, setter and getter functions for children, a function add_child() that takes a child argument and adds it to the list children, and a method get_total_earnings(). This method has no parameters and returns the computed total earnings over all children they supervised. A Child has setter and getter functions for its attributes rate and time_supervised, and a method compute_earnings(). This method returns the total earnings for babysitting for this child, based on rate and time_supervised. Note: Since this is OOP, each class needs an __init__() function