code: def weight_decay_is_fused(self):
      return self.weight_decouple
  
file_path: nnabla/python/test/solver/test_adabelief.py
imports: import pytest
  import nnabla.solvers
  import numpy
  from solver_test_utils import solver_tester, RefSolver
  from nbla_test_utils import list_context
label_desc: Use image node_id 2 for calling the RefAdaBelief obj's underlying member method code with example usage: obj.weight_decay_is_fused() and returns: self