code: def _sample_batch(self):
      return np.reshape(self._space.sample(), (1,) + self._space.shape)
  
imports: import gin
  import gym
  import numpy
  from tensorflow import test
  from trax.rl import space_serializer
label_desc: Use image node_id 2 for calling the MultiDiscreteSpaceSerializerTest obj's underlying member method code with example usage: obj._sample_batch() and returns: np