Problème code dict

import re
import os
import sys

dict = {'Dict1': {"Pomme": "Poire"},
        'Dict2': {"Banane": "Tomate"},
        'Dict3': {"fleur": "Arbre"},}

def find_END(line):
    if re.search(r'\bFIN\b', line):
        return True
    else:
        return False

def replacer_factory1(dictionary):
    def replacing(match):
        if len(dictionary) > 0:
            word = match.group()
            exchange = dictionary.get(word, word)
            return exchange
        else:
            return ""
    return replacing

def replacing1(text, dict):
    regex_patt_list = r'\b(?:' + '|'.join(dict) + r')\b'
    replacer = replacer_factory1(dict)
    return re.sub(regex_patt_list, replacer, text)



def folder(input,output):
    with open(sys.argv[1] + input) as fin:
        with open(sys.argv[1] + output, 'w') as fout:
            key = 0
            sous_dict = dict["Dict3"]
            cache_mem = []
            for line in fin:
                cache_mem.append(line)
                if find_END(line):
                    #print(cache_mem)
                    for x in cache_mem:
                        if x.strip() in dict.keys():
                            key = x.strip()
                            sous_dict = dict[key]
                        fout.write(replacing1(x,sous_dict))
                    cache_mem = []

print(sys.argv[0])
result = os.listdir(sys.argv[1])
for x in result:
    folder(x, x + "V")
print(result)