def apply_split_linear(lin_module_1,
                       lin_module_2,
                       input1,
                       input2,
                       activation=None):
  """Returns a linear output of two inputs, run independently and summed."""
  output_1 = lin_module_1(input1)
  output_2 = lin_module_2(input2)
  summed_output = output_1 + output_2
  if activation is not None:
    summed_output = activation(summed_output)
  return summed_output