Databunch object not getting saved

[Monk5088]

hey everyone ,
I tried saving my databunch object using databunch.save method but it gives me a ctype error:
Here is the code i used:

batch_size = 64

do_flip = True
flip_vert = True
max_rotate = 90
max_zoom = 1.1
max_lighting = 0.2
max_warp = 0.2
p_affine = 0.75
p_lighting = 0.75

tfms = get_transforms(do_flip=do_flip,
flip_vert=flip_vert,
max_rotate=max_rotate,
max_zoom=max_zoom,
max_lighting=max_lighting,
max_warp=max_warp,
p_affine=p_affine,
p_lighting=p_lighting)
train, valid = ObjectItemListSlide(train_images) ,ObjectItemListSlide(valid_images)
item_list = ItemLists(".", train, valid)
lls = item_list.label_from_func(lambda x: x.y, label_cls=SlideObjectCategoryList)
lls = lls.transform(tfms, tfm_y=True, size=patch_size)
data = lls.databunch(bs=batch_size, collate_fn=bb_pad_collate,num_workers=0).normalize()
The error:

ValueError Traceback (most recent call last)
in
----> 1 data.save("test_data_bs8.pkl")

3 frames
/usr/local/lib/python3.7/dist-packages/fastai/basic_data.py in save(self, file)
153 warn("Serializing the DataBunch only works when you created it using the data block API.")
154 return
--> 155 try_save(self.label_list, self.path, file)
156
157 def add_test(self, items:Iterator, label:Any=None, tfms=None, tfm_y=None)->None:

/usr/local/lib/python3.7/dist-packages/fastai/torch_core.py in try_save(state, path, file)
414 #To avoid the warning that come from PyTorch about model not being checked
415 warnings.simplefilter("ignore")
--> 416 torch.save(state, target)
417 except OSError as e:
418 raise Exception(f"{e}\n Can't write {path/file}. Pass an absolute writable pathlib obj fname.")

/usr/local/lib/python3.7/dist-packages/torch/serialization.py in save(obj, f, pickle_module, pickle_protocol, _use_new_zipfile_serialization)
378 if _use_new_zipfile_serialization:
379 with _open_zipfile_writer(opened_file) as opened_zipfile:
--> 380 _save(obj, opened_zipfile, pickle_module, pickle_protocol)
381 return
382 _legacy_save(obj, opened_file, pickle_module, pickle_protocol)

/usr/local/lib/python3.7/dist-packages/torch/serialization.py in _save(obj, zip_file, pickle_module, pickle_protocol)
587 pickler = pickle_module.Pickler(data_buf, protocol=pickle_protocol)
588 pickler.persistent_id = persistent_id
--> 589 pickler.dump(obj)
590 data_value = data_buf.getvalue()
591 zip_file.write_record('data.pkl', data_value, len(data_value))

ValueError: ctypes objects containing pointers cannot be pickled