docs: def __setup():
      """Will be executed in the first time someone calls classes_*() """
      global __collaborators, __flag_first
  
      import f311
  
      __flag_first = False
      for pkgname in f311.COLLABORATORS_C:
          try:
              pkg = importlib.import_module(pkgname)
              a99.get_python_logger().info("Imported collaborator package '{}'".format(pkgname))
  
              try:
                  if hasattr(pkg, "_setup_filetypes"):
                      pkg._setup_filetypes()
                  else:
                      _collect_classes(pkg)
  
                  __collaborators[pkgname] = pkg
              except:
                  a99.get_python_logger().exception(
                      "Actually, package '{}' gave error".format(pkgname))
                  raise
          except:
              a99.get_python_logger().warning("Failed to import package '{}".format(pkgname))