when append a directory to package 7z , some file raise Error

[SUNKANGhui]

Describe the bug
if adding one directory to a SevenZipFile, some files format like ".csv" or ".tiff"files in the directory is damaged.
but if writing a SevenzipFile with the directory , files written successfully, no problem to open
Related issue
(if exist)

To Reproduce
Steps to reproduce the behavior:
(example)

1. writing one file to to a SevenZipFile named demo.7z
2. add one directory or more directories to demo.7z
3. code:

import py7zr
out_file = r"D:/test/tmp/test/a/demo.7z"
with py7zr.SevenZipFile(out_file, 'w', password=None) as z:
    z.write(r"D:/test/tmp/test/a.xlsx", arcname="a.xlsx")
with py7zr.SevenZipFile(out_file, 'a', password=None) as z:
    z.writeall(r"D:/test/tmp/tmp/22", arcname="22")

4. res
   program run success , but some files like "a.csv" can not open.
   raise Error:Unknown format or incorrect password
   but if writing the directory ,file open successfully

Expected behavior

expect: it can work well as mode"w"

Environment (please complete the following information):

• OS: OS: Windows 10, 64-bit
• Python 3.7.0
• py7zr version: 0.17.2

Test data(please attach in the report):
source file here
demo.zip

Additional context
Add any other context about the problem here.

[miurahr]

There is no description , environmental conditions.

Describe the bug
A clear and concise description of what the bug is.

Please remove guidance sentence, and describe the bug clear and attach file when necessary to reproduce.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days

[miurahr]

when analyzing header after adding directory before close, I found empty list and file list is not consistent

EmptyFiles should be [False, True, False, False, ...] and length should be 8

[miurahr]

Changed the behavior finding above, and add more expectations for assertion.

https://github.com/miurahr/py7zr/pull/475/files

Any other wrong point?

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days