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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 _initialize(self):
 """ Open from caffe weights """

        self._graph = tf.Graph()
        with self._graph.as_default():
            self._input_node = tf.placeholder(tf.float32, (self._batch_size, self._im_height, self._im_width, self._num_channels))
            weights = self.build_alexnet_weights()
            self._output_tensor = self.build_alexnet(weights)
            self._feature_tensor = self.build_alexnet(weights, output_layer=self._feature_layer)
            self._initialized = True