def peek(self):
    "\n\t\tReturns the last item on the stack but doesn't remove it.\n\n\t\tTime Complexity: O(1)\n\n\t\t"
    return self.data[(- 1)]
Returns the last item on the stack but doesn't remove it.

Time Complexity: O(1)
def peek(self):
    "\n\t\tReturns the last item on the stack but doesn't remove it.\n\n\t\tTime Complexity: O(1)\n\n\t\t"
    return self.data[(- 1)]