message: Update the einsum op to handle python3 bytes correctly.
diff: @@ -137,6 +137,9 @@ def bessel_i1(x, name=None):
  @ops.RegisterGradient('XlaEinsum')
  def _einsum_grad(op, grad):
  equation = op.get_attr('equation')
  + if isinstance(equation, bytes):
  + equation = equation.decode()
  +
  inputs, output = equation.split('->')
  left, right = inputs.split(',')
  