These are the packages that would be merged, in order:

Calculating dependencies ...

!!! Problem resolving dependencies for =mail-client/claws-mail-4.3.1-r2
 done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=mail-client/claws-mail-4.3.1-r2" has unmet requirements.
- mail-client/claws-mail-4.3.1-r2::gentoo USE="dbus gnutls imap nls notification oauth pgp python smime -archive -bogofilter -calendar -clamav -debug -doc -ldap -litehtml -networkmanager -nntp -pdf -perl -rss -session -sieve -spam-report -spamassassin -spell -startup-notification -svg -valgrind -webkit -xface" PYTHON_SINGLE_TARGET="-python3_12 -python3_13"

  The following REQUIRED_USE flag constraints are unsatisfied:
    python? ( exactly-one-of ( python_single_target_python3_12 python_single_target_python3_13 ) )

  The above constraints are a subset of the following complete expression:
    networkmanager? ( dbus ) oauth? ( gnutls ) python? ( exactly-one-of ( python_single_target_python3_12 python_single_target_python3_13 ) ) smime? ( pgp )