photogroups.getPhotogroup(0).cameraModelBand : how to set camera model band manually in the scripts?

I found that the default value of "photogroups.getPhotogroup(0).cameraModelBand" is 'CameraModelBand_thermal' in a demo I used,
and if I try to set it to " CameraModelBand_visible, and there will be error message:

photogroups.getPhotogroup(0).cameraModelBand = 'CameraModelBand_visible'
Boost.Python.ArgumentError: Python argument types in
None.None(Photogroup, str)
did not match C++ signature:
So how to change camerModelBand from 'CameraModelBand_thermal' to 'CameraModelBand_visible'?

Thandk a lot