Python code, not able to write into xls

When the below code is executed in Python 3.5 and xlwt 1.2.0, following error is generated: "Cannot convert byte objects to str implicitly" The code works fine for python 2.7. Anyone please let me know what could be the problem. Thanks in Advance!!

    import xlwt
    import re
    import os

    wb = xlwt.Workbook()
    ws = wb.add_sheet('A Test Sheet')
    ws_1 = wb.add_sheet('A Test Sheet_B')
    cnt_row = 0
    cnt_col_1 = 0
    cnt_col_2 = 0


    path = "E:\Python_Scripts"
    files = os.listdir("E:\Python_Scripts")
    for filename in files:
        if filename.endswith(".ptu"):
            fo = open(os.path.join(path, filename), 'r')

            while(1):
                str = fo.readline()
                if (str == ""):
                    print ("file finished")
                    break
                else:
                    matchObj = re.match(r'\s*  TEST (.*?).*', str)
                    if (matchObj):
                        str = str.split('TEST', 1)[1]
                        ws.write(cnt_row, 0, str)
                        matchObj_Author = re.match(r' (.*)  Author (.*?).*', str)
                    if (matchObj_Author):
                        str = str.split('(', 1)[1]
                        str = str.rsplit(')', 1)
                        ws.write(cnt_row, 1, str)
                        cnt_row = cnt_row + 1

            fo.close()
   wb.save('example.xls')

Your data input has changed. And one or more of its lines contain multiple strings.

If you're reading a file where a line has multiple entires then your str will be a list not a string. If it is a list, this will cause the error when invoking wb.save('example.xls'): TypeError: must be str, not bytes

Here's a pared down version of your program that I used to test this out:

import xlwt
wb = xlwt.Workbook()
ws = wb.add_sheet('A Test Sheet')
ws_1 = wb.add_sheet('A Test Sheet_B')
cnt_row = 0
cnt_col_1 = 0
cnt_col_2 = 0

f = open('<an xml file with one string per line except the last line which has two strings', 'r', encoding='utf-8')
while 1:

    str = f.readline()
    wb.save('example.xls')
    if str == "":
        print ("file finished")
        break
    str = str.split('<', 1)[1]
    str = str.rsplit('<', 1)
    ws.write(cnt_row, 1, str)
    cnt_row = cnt_row + 1
    print('debug:last')
    print(str)
    print(type(str))

wb.save('example.xls')
f.close()