1. We want to add a button to the tally counter in Section 9.2 that allows an operator to undo an accidental button click. Provide a method def undo (self) that simulates such a button. As an added precaution, make sure an undo doesn't cause the counter to be less than zero. 5 pts a) Your code with comments b) A screenshot of the execution Test Case: Reset 2 clicks Print Value 1 click Print Value 2 undos Print Value 2 undos Print Value

See explaination

Explanation:

class Counter:

def getValue (self):

return self._value

def undo (self):

if self._value > 0:

self._value = self._value - 1;

def click (self):

self._value = self._value + 1

def reset (self):

self._value = 0

tally = Counter ()

tally. reset ()

tally. click ()

tally. click ()

result = tally. getValue ()

print ("Value:", result)

tally. click ()

result = tally. getValue ()

print ("Value:", result)

tally. undo ()

tally. undo ()

result = tally. getValue ()

print ("Value:", result)

tally. undo ()

tally. undo ()

result = tally. getValue ()

print ("Value:", result)