Can't install on Ubuntu 21.04 Hirsute Hippo

[christian-oudard]

$ sudo apt install bookworm 
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
bookworm is already the newest version (1.1.2+git20200823-1).
The following packages were automatically installed and are no longer required:
  libchm1 libjpeg-turbo-progs libllvm11 libllvm11:i386 libpodofo0.9.7 libqt5positioning5 libqt5quickwidgets5 libqt5webchannel5 libqt5webengine-data libqt5webengine5 libqt5webenginecore5 libqt5webenginewidgets5 libre2-9 libunibreak1
  libzlcore-data libzlcore0.13 libzltext-data libzltext0.13 libzlui-gtk optipng python3-apsw python3-chm python3-css-parser python3-cssselect python3-cssutils python3-feedparser python3-html2text python3-html5-parser python3-ifaddr
  python3-mechanize python3-py7zr python3-pyqt5.qtsvg python3-pyqt5.qtwebchannel python3-pyqt5.qtwebengine python3-regex python3-repoze.lru python3-routes python3-texttable python3-webob python3-zeroconf
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 2 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] Y
Setting up bookworm (1.1.2+git20200823-1) ...
  File "/usr/share/com.github.babluboy.bookworm/scripts/mobi_lib/mobiml2xhtml.py", line 249
    print "     - fixed by injecting empty start tag ", tname
          ^
SyntaxError: Missing parentheses in call to 'print'. Did you mean print("     - fixed by injecting empty start tag ", tname)?

dpkg: error processing package bookworm (--configure):
 installed bookworm package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 bookworm
E: Sub-process /usr/bin/dpkg returned an error code (1)

It appears that a python2 script is being executed with python3. The Python 2 executable is available as python2, but I don't know how to get it to execute here.

Installing with flatpak works fine.

[brikki]

Hello!
I am not know Python, but I slove this
open file for sudo in nano or vim or other text editor
/usr/share/com.github.bablu boy.bookworm/scripts/mobi lib/mobiml2xhtml.py
and replace your line for my(line number given)
On dev branch this problem fixed
249 print (' - fixed by injecting empty start tag ', tname)
255 print (' - fixed by injecting end tag ", self.path[-1]')
507 print ('Converting Mobi Markup Language to XHTML')
509 print ('Processing ...')
514 print ('Completed')
515 print ('XHTML version of book can be found at: ' + outname)
517 except ValueError es e:
518 print ('Error: %s', e)
524if name == 'main':

[andrewrproper]

I'm seeing the same problem.