code: def proto_from_str(nntxt_str):
      proto = nnabla_pb2.NNablaProtoBuf()
      text_format.Merge(nntxt_str, proto)
      return proto
  
imports: import os
  import io
  import pytest
  import numpy
  import nnabla
  import nnabla.functions
  from nnabla.testing import assert_allclose
  from contextlib import contextmanager
  from shutil import rmtree
  import tempfile
  import numpy
  import warnings
  from legacy_expander import NnpExpander
  from nnabla.utils import nnabla_pb2
  from legacy_load import _create_variable
  import google.protobuf.text_format
  from nnabla.utils.image_utils import imsave
  from nnabla.utils.get_file_handle import get_file_handle_save
  from nnabla.utils.nnp_format import nnp_version
label_desc: Use image node_id 10 for calling a global function with example usage: proto_from_str(nntxt_str) and returns: proto