code: def _POUpdateBuilderWrapper(env, target=None, source=_null, **kw):
    
    if source is _null:
      if 'POTDOMAIN' in kw:
        domain = kw['POTDOMAIN']
      elif 'POTDOMAIN' in env and env['POTDOMAIN']:
        domain = env['POTDOMAIN']
      else:
        domain = 'messages'
      source = [ domain ] # NOTE: Suffix shall be appended automatically
    return env._POUpdateBuilder(target, source, **kw)
docs: Wrapper for `POUpdate` builder - make user's life easier