Ex 7 Rock, Paper, Scissors Game

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Thu Jul 27 15:15:31 2017

@author: Jeff Garcia

Make a two-player Rock-Paper-Scissors game. (Hint: Ask for player plays 
(using input), compare them, print out a message of congratulations to the 
winner, and ask if the players want to start a new game)
"""

choices = ['Rock','Paper','Scissors', 'rock', 'paper', 'scissors']
restart = ['Yes', 'Y', 'yes', 'y', 'No', 'no', 'N', 'n']
again = 'Yes'

while again in ('Yes', 'Y', 'yes', 'y'):
    player1 = input("Player 1, do you choose rock, paper or scissors:")
    if player1 not in choices:
        input("Your only choices are rock, paper, or scissors:")

    player2 = input("Player 2, do you choose rock, paper or scissors:")
    if player2 not in choices:
        input("Your only choices are rock, paper, or scissors:")
    
    if player1 in ('Rock', 'rock') and player2 in ('Paper', 'paper'):
        print("Player 2 Wins!")
    elif player1 in ('Rock', 'rock') and player2 in ('Scissors', 'scissors'):
        print("Player 1 Wins!")
    elif player1 in ('Rock', 'rock') and player2 in ('Rock', 'rock'):
        print("It's a tie.")
    elif player1 in ('Paper', 'paper') and player2 in ('Rock', 'rock'):
        print("Player 1 Wins!")
    elif player1 in ('Paper', 'paper') and player2 in ('Scissors', 'scissors'):
        print("Player 2 wins!")
    elif player1 in ('Paper', 'paper') and player2 in ('Paper', 'paper'):
        print("It's a tie.")
    elif player1 in ('Scissors', 'scissors') and player2 in ('Rock', 'rock'):
        print("Player 2 wins!")
    elif player1 in ('Scissors', 'scissors') and player2 in ('Paper', 'paper'):
        print("Player 1 wins!")
    elif player1 in ('Scissors', 'scissors') and player2 in ('Scissors', 'scissors'):
        print("It's a tie.")

    again = input("Would you like to play again?")
    while again not in restart:
        again = input("Would you like to play again?")