code: def reset(self, indices=None):
      
      return tf.cond(
          tf.cast(tf.reduce_sum(indices + 1), tf.bool),
          lambda: self._reset_non_empty(indices),
          lambda: tf.cast(0, self.observ_dtype))
docs: Reset the batch of environments.
  
      Args:
        indices: The batch indices of the environments to reset.
  
      Returns:
        Batch tensor of the new observations.