My crack at python

[T8y8]

I recently started teaching myself python (after searching the threads for recommendations). Right now I am working on a Rock, Paper, Scissors program to mess around with if...then, definitions, and booleans, which is why the program might seem odd, I have the WIN/LOSE based off of Bool's, but I wanted to practice using them.

Right now I'm trying to figure out a way to integrate a check to see if the player is actually putting in rock, paper, or scissors, but I haven't gotten anything to work yet. I have it checking for membership in the list picks, but I'm not sure how to make that 'reset' or try again.

Any ideas?

#!/usr/bin/env python
# filename : rps.py

# Author: T8y8
# A Rock, Paper, Scissors game

#Imports
import random
import sys
#Define Variables
menu = '''
=================================
Welcome to Rock, Paper, Scissors!
Press enter to continue
Quit at anytime by typing 'quit'
=================================
'''
picks = ['rock', 'paper', 'scissors']

#Computer Chooses
def computerPick():
    global compChoice
    compChoice = random.choice(picks)
#Player Chooses
def playerPick():
    global playerChoice
    playerChoice = raw_input("Rock, Paper, or Scissors?")
    if playerChoice.lower() == 'quit':
        sys.exit()
    if playerChoice.lower() not in picks:
        print ' That is not an option'
def choiceCompare(x, y): # X is Comp, Y is Person
    global win
    win = False
    if not win:
        if x == 'rock':
            if y.lower() == 'paper':
                win = True
        elif x == 'paper':
            if y.lower() == 'scissors':
                win = True
        elif x == 'scissors':
            if y.lower() == 'rock':
                win = True
#Show menu
c = raw_input(menu)
# Game Loop
while c != 'quit':
        computerPick()
        playerPick()
        choiceCompare(compChoice, playerChoice)
        if win is True:
            print "You beat %s with %s" % (compChoice, playerChoice)
        elif playerChoice == compChoice:
            print "YOU TIED WITH %s" % compChoice
        else:
            print "You lost to %s with %s" % (compChoice, playerChoice)

[SomeoneE1se]

try the code with out using functions.