BUG: Merge commits are displayed by `--cherry-pick` despite on they introduce same change

The --cherry-pick option states:

For next git command I see next tree:

    $ git log --graph --decorate --pretty=oneline --abbrev-commit --cherry-mark --boundary --left-right

< bc2820d (openapi3) Merge branch 'openapi3_exception_handling' into openapi3
|\
| = 4e1e0aa Testcase for not_found/exception requests to api
| = b39673d 'not_found' templates should not be probed automatically. Only when fallback | = a8677df Dump empty schemas and non empty data
| = 27db48f Implemente before_render hook
|/
< aa60f0a Merge branch 'hide_temporal_interface' into openapi3
|\
| = 5dd02f2 Mutate current object after update
| = d58c0ab Install missed modules
|/
| > b8d09ce (xtucha/openapi3) Merge branch 'openapi3_exception_handling' into openapi3
| |\
| | = b6362ad Testcase for not_found/exception requests to api
| | = dc926cc 'not_found' templates should not be probed automatically. Only when fallback | | = 55dc88d Dump empty schemas and non empty data
| | = 8369185 Implemente before_render hook
| |/
| > c03438d Merge branch 'hide_temporal_interface' into openapi3
| |\
| | = d534cc4 Mutate current object after update
| | = 1b6af27 Install modules required by MonkeyMan
| |/
| > a3b7230 Clarify schema
|/
o f5b06ed Assign some defaults

If I want to see only new commit I add --left-only option and get merge commits in output.

< bc2820d (openapi3) Merge branch 'openapi3_exception_handling' into
< aa60f0a Merge branch 'hide_temporal_interface' into openapi3

This commits introduce same change as another merge commit on the "other side" Thus they should not be displayed