代码未按预期写入子目录,内存使用率很高

import xmltodict
import numpy as np
import pandas as pd
from collections import Counter
import os
import glob
import re

#from list of directories, iterate through each directory and apply my functions    
def change_dir (directories):
    for i in directories:
        os.chdir(i)  
        return parse_xml (i)

#Read xml files from each subdir,parse and append to a list            
def parse_xml (subdirectory):
    doc = []
    for i in glob.glob(os.path.join(subdirectory, '*.xml')):
        with open(i, 'r') as fd:
            doc.append(xmltodict.parse(fd.read()))
    return make_pandas(doc)

#Take list of each subdir xml files, create required df and write csv to subdir
def make_pandas (list_parsedFiles):
    logData_list = []
    for xmlval in list_parsedFiles:
        channel_list = xmlval['logs']['log']['logData']['mnemonicList'].split(",")
        temp = [i.split(",") for i in xmlval ['logs']['log']['logData']['data']]
        temp.insert(0, xmlval ['logs']['log']['logData']['unitList'].split(","))
        logData_list.extend(temp)
        df = pd.DataFrame(np.array(logData_list).reshape(len(logData_list),len(channel_list)), columns = channel_list).drop_duplicates()
        df.to_csv('out.csv')

%%capture
tocsv = change_dir (list_smallLogs)