Pokemon game in python: classes/objects, battle and deepcopy

I'm new on python and I'm trying to do a Pokemon game (like the gameboy and nds games). I've created the pokemon and trainer classes and I want to implement the battle mechanics. I thought it was working fine, but then I found that if I loose the battle the program enters in an infinite loop. I tried a lot to found the error and I discovered that when it exits the while alive(pokemon1) and alive(pokemon2) loop, the pokemon1 hp returns to full hp but the pokemon2 remains with the current hp. It makes non sense for me because the code is identical for both. Anyone knows why is it happening? I want it to return the current hp of both pokemon.

Here is a sample of my code showing the error:

import copy
import random

class Pokemon(object):
    def __init__(self, name, hp):
        self.name = name
        self.hp = hp
    def ataque(self, oponent):
        oponent.hp = oponent.hp - 150 #just for a test

class Trainer(object):
    def __init__(self, name, *pokemon):
        self.name = name
        self.pokemon, self.pokemonname = [], []
        for pkmn in pokemon:
            self.pokemon.append(copy.deepcopy(pkmn))
            self.pokemonname.append(pkmn.name)

weavile = Pokemon ('Weavile', 150) #change the hp to more than 150 if you want to win
garchomp = Pokemon ('Garchomp', 250)
roserade = Pokemon ('Roserade', 160)
ambipom = Pokemon ('Ambipom', 160) 

eu = Trainer('You', weavile) #or choose ambipom to win
cynthia = Trainer('Cynthia', garchomp)

def alive(pokemon): #check if the pokemon is alive
    if pokemon.hp>0:
        return True
    if pokemon.hp<=0:
        pokemon.hp=0
        return False

def battle(trainer1, trainer2): #battle between two trainers
    fight1, fight2 = True, True
    while fight1 and fight2:
        print ('Choose a pokemon:', trainer1.pokemonname)
        pokemon1 = eval(input())
        while not alive(pokemon1):
            print (pokemon1.name, 'is out of batlle. Choose another pokemon')
            pokemon1 = eval(input())
        pokemon2 = random.choice(trainer2.pokemon)
        while not alive(pokemon2):
            pokemon2 = random.choice(trainer2.pokemon)
        print (trainer1.name, 'chose', pokemon1.name, '\n', trainer2.name, 'chose', pokemon2.name)
        while alive(pokemon1) and alive(pokemon2):
            pokemon1.ataque(pokemon2)
            if alive(pokemon2):
                pokemon2.ataque(pokemon1)
            print (pokemon1.name, pokemon1.hp)
            print (pokemon2.name, pokemon2.hp)
        print (trainer1.pokemon[0].name, trainer1.pokemon[0].hp) #here its returning the original hp
        print (trainer2.pokemon[0].name, trainer2.pokemon[0].hp) #here its returning the current hp, as it should
        if not any(alive(pokemon) for pokemon in trainer1.pokemon):
            fight1 = False
        if not any(alive(pokemon) for pokemon in trainer2.pokemon):
            fight2 = False

battle(eu, cynthia)