docs: def get_keys(self, key=None):
          """
              Returns a list of valid sub-keys.
          """
          if key:
              value = _lxc.Container.get_keys(self, key)
          else:
              value = _lxc.Container.get_keys(self)
  
          if value is False:
              return False
          elif value.endswith("\n"):
              return value.rstrip("\n").split("\n")
          else:
              return value