Debian install fails - python2 print (instead of print( ) )

Trying (and failing) to install on Debian:

```
====== How can you help? (doc: https://wiki.debian.org/how-can-i-help ) ======

----- Show old opportunities as well as new ones: how-can-i-help --old -----
E: Sub-process /usr/bin/dpkg returned an error code (1)
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
Press Return to continue, 'q' followed by Return to quit.
```

Linux 4.19.0-4-amd64 #1 SMP Debian 4.19.28-2 (2019-03-15) x86_64 GNU/Linux

Start with scripts/mobi_lib/mobiml2xhtml.py at line 249 and reproduce the Debian package configuration failure. Check the surrounding script for the reported Python 2 syntax, then verify that installing and configuring bookworm completes without the shown SyntaxError.

Written by the indexing model from the issue text.