def _mean(W_or_V):
    """ The reconstruction from VAE is returned by:
  (mean, total_stddev, explained_stddev)
  This method will make sure only mean value is return
  """
    W_or_V = W_or_V[0] if isinstance(W_or_V, (tuple, list)
        ) or W_or_V.ndim == 3 else W_or_V
    assert W_or_V.ndim == 2
    return W_or_V
