def select(self, query, multiple):
raise NotImplementedError<EOL>
Select UI element(s) matching the given query expression and return the list of selected UI element(s)

Args:
    query (:obj:`tuple`): query expression,  for the structure specification refer to
     :py:class:`Selector <poco.sdk.Selector>`.
    multiple (:obj:`bool`): whether or not to select multiple elements,  if False, the method terminates \
    immediately once the node is found, otherwise the method travers through all nodes and then terminates

Returns:
    :obj:`list` : list of UI elements corresponding to the given query expression