print a warning if the user want to freeze the index and the model is not a powerlaw
print a warning if the user want to freeze the index and the model is not a powerlaw

dailytimes/enrico,gammapy/enrico,mireianievas/enrico,migueln/enrico,mireianievas/enrico,migueln/enrico,dailytimes/enrico,gammapy/enrico