string manipulation

[yogi123]

I need to replace parts of a string with what it matches in a dictionary. I have restrictions and to change strings only functions i can use are .strip, .split, .append, .join, .format. I cant use replace.

def sub(my_dict, phrase):
    for keys, values in my_dict.items():
        s = phrase.split(keys)
        phrase = values.join(s)
    return phrase
my_dict = { 'c':'.', 'p':'f', 'a':'g', 'l':'e', 'e':'l', ' ':'o' }
phrase = "ape pea lap"

should return gfloflgoegf

I return gfloflgolgf