code: def test_log1pexp_to_softplus(self):
      m = theano.config.mode
      if m == "FAST_COMPILE":
          m = "FAST_RUN"
  
      x = T.vector()
  
      out = T.log(1 + T.exp(x))
      f = theano.function([x], out, mode=self.m)
  
      # Fix ticket #4581 first
      # assert check_stack_trace(f, ops_to_check='all')
      topo = f.maker.fgraph.toposort()
      assert len(topo) == 1
      assert isinstance(
          topo[0].op.scalar_op, theano.tensor.nnet.sigm.ScalarSoftplus
      )
      f(np.random.rand(54).astype(config.floatX))
  
imports: from __future__ import absolute_import, print_function, division
  import unittest
  import numpy
  from theano.compat import imap
  import theano.tensor.inplace
  from theano.tensor import basic
  from theano import tensor
  from theano import config
  from theano.gof.opt import check_stack_trace
  from theano.tests import unittest_tools
  from theano.tensor.nnet import sigmoid, sigmoid_inplace, softplus, ultra_fast_sigmoid, hard_sigmoid
  from theano.tensor.nnet.sigm import compute_mul, is_1pexp, parse_mul_tree, perform_sigm_times_exp, register_local_1msigmoid, simplify_mul
  from theano.tensor.tests.test_basic import makeBroadcastTester, copymod, check_floatX, upcast_int8_nfunc, _good_broadcast_unary_normal_no_complex
label_desc: Use image node_id 4 for calling the T_softplus_opts obj's underlying member method code with example usage: obj.test_log1pexp_to_softplus() without return types