code: def forward(self, inputs, device):
      (x,) = inputs
      return (functions.log1p(x),)
  
file_path: chainer/tests/chainer_tests/functions_tests/math_tests/test_logarithm_1p.py
imports: import numpy
  from chainer import functions
  from chainer import testing
  from chainer.utils import force_array
label_desc: Use image node_id 2 for calling the Log1pFunctionTest obj's underlying member method code with example usage: obj.forward(inputs, device) and returns: functions