I have removed some minor bugs. All credit goes to @abarnert

import random

def symmetric_enc(message, key):
    return [ord(char) ^ key for char in message]

def symmetric_dec(cipher, key) :
    return [num ^ key for num in cipher]

def asymmetric_enc(message, pubkey) :
    e,n = pubkey
    c = pow(message,e,n)
    return c

def asymmetric_dec(cipher, prikey) :
    d,n = prikey
    message = pow(cipher,d,n)
    return message

def enc(message, pubkey):
    session_key = random.randrange(1, 256)
    return (asymmetric_enc(session_key, pubkey),
            symmetric_enc(message, session_key))

def dec(message, prikey):
    session_key, body = message
    session_key = asymmetric_dec(session_key, prikey)
    msg = symmetric_dec(body, session_key)
    message = ''.join([chr(m) for m in msg])
    return message

n = 3337
e = 79
d = 1019

pubkey = (e, n)
prikey = (d, n)

msg = 'Hello World!'
print(msg)
cipher = enc(msg, pubkey)
print('-------')
for c in cipher : print(c,)
print('-------')
decipher = dec(cipher, prikey)
print(decipher)