code: def pysourcefiles(self):
          
          sourcefiles = set()
          for (name, child) in vars(self).items():
              try:
                  parents = inspect.getmro(child)
              except AttributeError:
                  continue
              for parent in parents:
                  try:
                      sourcefile = inspect.getfile(parent)
                  except TypeError:
                      break
                  sourcefiles.add(sourcefile)
          return Lines(*sourcefiles)
docs: All source files of the actual models Python classes and their
          respective base classes.