code: def add_settings(mod, allow_extras=True, settings=django_settings):
      
      extras = {}
  
      for setting in dir(mod):
          if setting == setting.upper():
              setting_value = getattr(mod, setting)
              if setting in TUPLE_SETTINGS and type(setting_value) == str:
                  setting_value = (setting_value,)  # In case the user forgot the comma.
  
              # Any setting that starts with EXTRA_ and matches a setting that is a list or tuple
              # will automatically append the values to the current setting.
              # It might make sense to make this less magical
              if setting.startswith('EXTRA_'):
                  base_setting = setting.split('EXTRA_', 1)[-1]
                  if isinstance(getattr(settings, base_setting), (list, tuple)):
                      extras[base_setting] = setting_value
                      continue
  
              setattr(settings, setting, setting_value)
  
      for key, value in extras.items():
          curval = getattr(settings, key)
          setattr(settings, key, curval + type(curval)(value))
docs: Adds all settings that are part of ``mod`` to the global settings object.
  
      Special cases ``EXTRA_APPS`` to append the specified applications to the
      list of ``INSTALLED_APPS``.