Trying to code a rock , paper, scissors game in Python

When the input is 'r' it works perfectly but when the input is 'p' or 'r' it just adds up these two letters to the word 'scissors´ from the input phrase

import random
def play():
   user = input("'r' for rock, 'p' for paper, 's' for scissors")
   computer = random.choice(['r','p','s'])

    if user == computer:
        return 'It`s a tie!'

    # r > s, s > p, p > r
    if is_win(user, computer):
        return 'You won!'

    return 'You lost'

def is_win(player, opponent):
    #return true if player wins
    #r>s, s>p, p>r
    if(player == 'r' and opponnent == 's') or (player == 's' and opponnent == 'p') or \
        (player == 'p' and opponnent == 'r'):
        return True