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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def build_list(self, title=None, items=None):
 """Presents the user with a vertical list of multiple items. Allows the user to select a single item. Selection generates a user query containing the title of the list item *Note* Returns a completely new object, and does not modify the existing response object Therefore, to add items, must be assigned to new variable or call the method directly after initializing list example usage: simple = ask('I speak this text') mylist = simple.build_list('List Title') mylist.add_item('Item1', 'key1') mylist.add_item('Item2', 'key2') return mylist Arguments: title {str} -- Title displayed at top of list card Returns: _ListSelector -- [_Response object exposing the add_item method] """


        list_card = _ListSelector(
            self._speech, display_text=self._display_text, title=title, items=items
        )
        return list_card