code: def save_model_from_graph_def_save(
      nnp_file, model_def, input_shape, variable_batch_size
  ):
      with nn.graph_def.graph() as g:
          x = nn.ProtoVariable(input_shape)
          y = model_def(x)
      g.save(nnp_file, variable_batch_size=variable_batch_size)
  
imports: import pytest
  import numpy
  import nnabla
  import nnabla.functions
  import nnabla.parametric_functions
  from nnabla.utils import load
  from nnabla.utils import save
  from nnabla.utils import nnp_graph
  from helper import forward_variable, create_temp_with_dir
label_desc: Use image node_id 11 for calling a global function with example usage: save_model_from_graph_def_save(nnp_file, model_def, input_shape, variable_batch_size) without return types