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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 append(self, value):
 """ Append an item to the end of an open ConsList. Args: value (:class:`Conjunction`, :class:`Term`):
 item to add Raises: :class:`TdlError`: when appending to a closed list """

        if self._avm is not None and not self.terminated:
            path = self._last_path
            if path:
                path += '.'
            self[path + LIST_HEAD] = value
            self._last_path = path + LIST_TAIL
            self[self._last_path] = AVM()
        else:
            raise TdlError('Cannot append to a closed list.')