The function main continually asks the user for a string, and calls isPalindrome to check whether each string is a palindrome.

A palindrome is a word or sequence that reads the same backward as forward, e.g., noon, madam or nurses run.

The function must ignore spaces: when the user enters 'nurses run', the function returns True, to indicate that it is a palindrome.

In the code (in isPalindrome) , stack must be used to determine whether the input strings are palindromes. The program imports the Stack class

Do not make any changes to main() or to stack.py.

stack.py

""" File: stack.py

Stack class: Simple implementation of a stack using lists. """

class Stack: def __init__(self): self.items = []

def isEmpty(self): return self.items == []

def push(self, item): self.items.append(item)

def pop(self): return self.items.pop()

def peek(self): return self.items[len(self.items)-1]

def size(self): return len(self.items)

File do modify (except for main)

""" File: a5.py

"""

from stack import Stack

def isPalindrome(sentence): """Returns True if sentence is a palindrome or False otherwise.""" stk = Stack() # Creates a stack called stk.

# *** Write your code here *** return True

# *** Do not modify main() *** def main(): while True: sentence = input("Enter some text or just hit Enter to quit: ") if sentence == "": break elif isPalindrome(sentence): print("It's a palindrome.") else: print("It's not a palindrome.")

main()