python 将doc格式转docx格式错误 'Microsoft Word', Sorry, we couldn't find your file

import os
from win32com import client as wc
path = r"C:\Users\qinh\Desktop\doc"
files = []
for file in os.listdir(path):
    if file.endswith(".doc"):
        files.append(path+file)
print(files)

word = wc.Dispatch("Word.Application")
i = 0
for file in files:
    doc = word.Documents.Open(file)
    doc.SaveAs("{}x".format(file), 12)
    doc.Close()
    print(file+"转化成功")
    i += 1
word.Quit()

运行结果
['C:\Users\qinh\Desktop\docBSH-787-21-127-00-01.doc', 'C:\Users\qinh\Desktop\docBSH-787-23-005-00-01.doc', 'C:\Users\qinh\Desktop\docBSH-787-23-020-00-01.doc', 'C:\Users\qinh\Desktop\docBSH-787-27-200-00-01.doc', 'C:\Users\qinh\Desktop\docBSH-787-27-230-00-01.doc', 'C:\Users\qinh\Desktop\docBSH-787-28-010-00-01.doc', 'C:\Users\qinh\Desktop\docBSH-787-52-805-01-01.doc', 'C:\Users\qinh\Desktop\docBSH-787-54-810-01-01.doc', 'C:\Users\qinh\Desktop\docBSH-787-78-045-01-01.doc', 'C:\Users\qinh\Desktop\docBSH-787-78-050-01-01.doc']
Traceback (most recent call last):
File "C:/Users/qinh/AppData/Roaming/JetBrains/PyCharmCE2021.1/scratches/doc_docx.py", line 13, in
doc = word.Documents.Open(file1)
File "<COMObject >", line 5, in Open
pywintypes.com_error: (-2147352567, 'Exception occurred.', (0, 'Microsoft Word', "Sorry, we couldn't find your file. Was it moved, renamed, or deleted?\r (C:\Users\...\docBSH-787-21-127-00-01.doc)", 'wdmain11.chm', 24654, -2146823114), None)

如果doc是个文件夹的话：
从代码第七行和报错第一行信息来看，路径错了
第七行括号里应该是files.append(path+''+file)