When renaming channels via https://mne.tools/stable/generated/mne.rename_channels.html and a particular channel is present in the renaming map but not the object, then an error is raised.

It would be convenient to control this behavior with an on_missing parameter like we have for example for set_annotations: https://mne.tools/stable/generated/mne.Epochs.html#mne.Epochs.set_annotations

The options would be "raise" (default, backward compatible), "warn", and "ignore".