Scheme representing agnpy’s modules, their relations and the computations they perform. agnpy.emission_regions, defining the region responsible for the non-thermal radiation (containing the EED), is the initialising argument of the classes modelling radiative processes and computing their SEDs (agnpy.synchrotron and agnpy.compton). Thermal and line emitters, collected in agnpy.targets, are initialising arguments of the modules for the external Compton and the γγ absorption calculations (agnpy.absorption). The targets’ thermal SEDs and energy densities (u) can also be computed. The emission region is passed to the class for self-consistent modelling (agnpy.constraints) and to the absorption class to compute the γγ absorption on synchrotron photons.