docs: def _load(self):
          """ Loads a model into weights """
          if self._model_filename is None:
              raise ValueError('Model filename not specified')
  
          # read the input image
          self._graph = tf.Graph()
          with self._graph.as_default():
              # read in filenames
              reader = tf.train.NewCheckpointReader(self._model_filename)
  
              # load AlexNet weights
              weights = AlexNetWeights()
              weights.conv1W = tf.Variable(reader.get_tensor("Variable")) 
              weights.conv1b = tf.Variable(reader.get_tensor("Variable_1"))
              weights.conv2W = tf.Variable(reader.get_tensor("Variable_2"))
              weights.conv2b = tf.Variable(reader.get_tensor("Variable_3"))
              weights.conv3W = tf.Variable(reader.get_tensor("Variable_4"))
              weights.conv3b = tf.Variable(reader.get_tensor("Variable_5"))
              weights.conv4W = tf.Variable(reader.get_tensor("Variable_6"))
              weights.conv4b = tf.Variable(reader.get_tensor("Variable_7"))
              weights.conv5W = tf.Variable(reader.get_tensor("Variable_8"))
              weights.conv5b = tf.Variable(reader.get_tensor("Variable_9"))
              weights.fc6W = tf.Variable(reader.get_tensor("Variable_10"))
              weights.fc6b = tf.Variable(reader.get_tensor("Variable_11"))
              weights.fc7W = tf.Variable(reader.get_tensor("Variable_12"))
              weights.fc7b = tf.Variable(reader.get_tensor("Variable_13"))
              weights.fc8W = tf.Variable(reader.get_tensor("Variable_14"))
              weights.fc8b = tf.Variable(reader.get_tensor("Variable_15"))
  
              # form network
              self._input_node = tf.placeholder(tf.float32, (self._batch_size, self._im_height, self._im_width, self._num_channels))
              self._output_tensor = self.build_alexnet(weights)
              self._feature_tensor = self.build_alexnet(weights, output_layer=self._feature_layer)
              self._initialized = True