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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 _swap(self, class1, class2, a):
 """evaluate cost of moving a from class1 to class2"""

        ss1 = self._ss(class1)
        ss2 = self._ss(class2)
        tss1 = ss1 + ss2
        class1c = copy.copy(class1)
        class2c = copy.copy(class2)
        class1c.remove(a)
        class2c.append(a)
        ss1 = self._ss(class1c)
        ss2 = self._ss(class2c)
        tss2 = ss1 + ss2
        if tss1 < tss2:
            return False
        else:
            return True