class_docstr: DataGenerator callback base class.
  
  To build your own callbacks, inherit `mz.data_generator.callbacks.Callback`
  and overrides corresponding methods.
  
  A batch is processed in the following way:
  
  - slice data pack based on batch index
  - handle `on_batch_data_pack` callbacks
  - unpack data pack into x, y
  - handle `on_batch_x_y` callbacks
  - return x, y
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docstr: `on_batch_unpacked`.
  
  :param x: unpacked x.
  :param y: unpacked y.
docstr_tok: ["`","on_batch_unpacked","`",".",":","param","x",":","unpacked","x.",":","param","y",":","unpacked","y","."]
code: def on_batch_unpacked(self, x: dict, y: np.ndarray):
      """
      `on_batch_unpacked`.
  
      :param x: unpacked x.
      :param y: unpacked y.
      """
  
imports: import numpy
  import matchzoo
label_desc: Use image node_id 2 for calling the Callback obj's underlying member method code with example usage: obj.on_batch_unpacked(x, y) without return types