error in convert ipynb to py

[joscani]

Hi.
I'm using debian bullseye.
I have a problem convert ipynb file to py file

Error detected while processing function jukit#convert#notebook_convert[5]..<SNR>67_convert_to_script:                                                                                        
line   12:                                                                                                                                                                                    
E319: No "python3" provider found. Run ":checkhealth provider" 

but I have python3 installed and if i press os and ipython is opened in a terminal buffer. any idea?