code: def test_prune_double_backward(rate, seed, ctx, func_name):
      from nbla_test_utils import backward_function_tester
  
      rng = np.random.RandomState(seed)
      inputs = [rng.randn(2, 3, 4).astype(np.float32) * 2]
  
      backward_function_tester(
          rng, F.prune, inputs, func_args=[rate], ctx=ctx
      )
  
file_path: nnabla/python/test/function/test_prune.py
imports: import pytest
  import numpy
  import nnabla.functions
  from nbla_test_utils import list_context
label_desc: Use image node_id 4 for calling a global function with example usage: test_prune_double_backward(rate, seed, ctx, func_name) without return types