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

Calculating dependencies ...

!!! Problem resolving dependencies for =mail-filter/courier-pythonfilter-3.0.4
 done!
Dependency resolution took 0.83 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "=mail-filter/courier-pythonfilter-3.0.4" has unmet requirements.
- mail-filter/courier-pythonfilter-3.0.4::gentoo USE="" PYTHON_TARGETS="-python3_12"

  The following REQUIRED_USE flag constraints are unsatisfied:
    python_targets_python3_12

  The above constraints are a subset of the following complete expression:
    any-of ( python_targets_python3_12 )