# AttributeError: can't set atttribute

**URL:** <https://discuss.ray.io/t/attributeerror-cant-set-atttribute/8985>\
**Category:** Ray Core\
**Created:** [January 16, 2023, 4:42pm UTC](https://discuss.ray.io/t/attributeerror-cant-set-atttribute/8985 "2023-01-16T16:42:49Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![pierre-manchon](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/pierre-manchon/32/3729_2.png) [@pierre-manchon](https://discuss.ray.io/u/pierre-manchon)\
**Post date:** [January 16, 2023, 4:42pm UTC](https://discuss.ray.io/t/attributeerror-cant-set-atttribute/8985/1 "2023-01-16T16:42:50Z")

</div>

**How severe does this issue affect your experience of using Ray?**

- High: It blocks me to complete my task.

**INSTALLATION INFORMATIONS** :  
OS: Ubuntu 20.04.5 LTS  
Python: 3.8.13  
Ray: 1.12.1

_CONDA INFO_

```auto
     active environment : sisppeo-dev
    active env location : /nfs/.../conda/.../envs/sisppeo-dev
            shell level : 2
       user config file : /local/.../.condarc
 populated config files : /local/.../.condarc
          conda version : 4.12.0
    conda-build version : 3.21.5
         python version : 3.9.7.final.0
       virtual packages : __linux=5.4.0=0
                                    __glibc=2.31=0
                                    __unix=0=0
                                    __archspec=1=x86_64
       base environment : /opt/anaconda3 (read only)
      conda av data dir : /opt/anaconda3/etc/conda
  conda av metadata url : None
           channel URLs : https://conda.anaconda.org/conda-forge/linux-64
                                    https://conda.anaconda.org/conda-forge/noarch
                                    https://conda.anaconda.org/anaconda/linux-64
                                    https://conda.anaconda.org/anaconda/noarch
                                    https://repo.anaconda.com/pkgs/main/linux-64
                                    https://repo.anaconda.com/pkgs/main/noarch
                                    https://repo.anaconda.com/pkgs/r/linux-64
                                    https://repo.anaconda.com/pkgs/r/noarch
          package cache : /nfs/.../conda/pkgs
       envs directories : /nfs/.../conda/.../envs
                                   /local/.../.conda/envs
                                   /opt/anaconda3/envs
               platform : linux-64
             user-agent : conda/4.12.0 requests/2.26.0 CPython/3.9.7 Linux/5.4.0-122-generic ubuntu/20.04.5 glibc/2.31
                UID:GID : 2457:9003
             netrc file : None
           offline mode : False

```

_CONDA LIST_

```auto
# Name Version Build Channel
_libgcc_mutex 0.1 conda_forge conda-forge
_openmp_mutex 4.5 2_gnu conda-forge
aenum 3.1.11 pyhd8ed1ab_0 conda-forge
affine 2.3.1 pyhd8ed1ab_0 conda-forge
aiosignal 1.2.0 pyhd8ed1ab_0 conda-forge
alabaster 0.7.12 pypi_0 pypi
aom 3.5.0 h27087fc_0 conda-forge
appdirs 1.4.4 pyh9f0ad1d_0 conda-forge
attrs 22.1.0 pyh71513ae_1 conda-forge
babel 2.10.3 pypi_0 pypi
beautifulsoup4 4.11.1 pypi_0 pypi
blessings 1.7 py38h578d9bd_1006 conda-forge
blinker 1.5 pyhd8ed1ab_0 conda-forge
blosc 1.21.1 h83bc5f7_3 conda-forge
bokeh 2.4.3 pypi_0 pypi
boost-cpp 1.78.0 h75c5d50_1 conda-forge
boto3 1.24.85 pyhd8ed1ab_0 conda-forge
botocore 1.27.85 pyhd8ed1ab_0 conda-forge
brotli 1.0.9 h166bdaf_7 conda-forge
brotli-bin 1.0.9 h166bdaf_7 conda-forge
brotlipy 0.7.0 py38h0a891b7_1004 conda-forge
brunsli 0.1 h9c3ff4c_0 conda-forge
bzip2 1.0.8 h7f98852_4 conda-forge
c-ares 1.18.1 h7f98852_0 conda-forge
c-blosc2 2.4.2 h7a311fb_0 conda-forge
ca-certificates 2022.9.24 ha878542_0 conda-forge
cached-property 1.5.2 hd8ed1ab_1 conda-forge
cached_property 1.5.2 pyha770c72_1 conda-forge
cairo 1.16.0 ha61ee94_1014 conda-forge
certifi 2022.9.24 pyhd8ed1ab_0 conda-forge
cf_xarray 0.7.4 pyhd8ed1ab_0 conda-forge
cffi 1.15.1 py38h4a40e3a_0 conda-forge
cfgv 3.3.1 pyhd8ed1ab_0 conda-forge
cfitsio 4.1.0 hd9d235c_0 conda-forge
cftime 1.6.2 py38h26c90d9_0 conda-forge
charls 2.3.4 h9c3ff4c_0 conda-forge
charset-normalizer 2.1.1 pyhd8ed1ab_0 conda-forge
click 8.1.3 py38h578d9bd_0 conda-forge
click-plugins 1.1.1 py_0 conda-forge
cligj 0.7.2 pyhd8ed1ab_1 conda-forge
cloudpickle 2.2.0 pyhd8ed1ab_0 conda-forge
colorama 0.4.5 pyhd8ed1ab_0 conda-forge
colorcet 3.0.0 pyhd8ed1ab_0 conda-forge
cryptography 37.0.1 py38h9ce1e76_0 anaconda
curl 7.85.0 h2283fc2_0 conda-forge
cycler 0.11.0 pyhd8ed1ab_0 conda-forge
cytoolz 0.12.0 py38h0a891b7_0 conda-forge
dask-core 2022.9.2 pyhd8ed1ab_0 conda-forge
dataclasses-json 0.5.7 pyhd8ed1ab_0 conda-forge
datashader 0.14.2 pyh6c4a22f_0 conda-forge
datashape 0.5.4 py_1 conda-forge
dav1d 1.0.0 h166bdaf_1 conda-forge
distlib 0.3.5 pyhd8ed1ab_0 conda-forge
distributed 2022.8.1 pypi_0 pypi
docutils 0.17.1 pypi_0 pypi
ephem 4.1.3 py38h0a891b7_4 conda-forge
esmf 8.2.0 nompi_h1ee4d8d_2 conda-forge
esmpy 8.2.0 nompi_py38h6633fd3_1 conda-forge
expat 2.4.9 h27087fc_0 conda-forge
filelock 3.8.0 pyhd8ed1ab_0 conda-forge
fiona 1.8.21 py38hd65b8f4_2 conda-forge
font-ttf-dejavu-sans-mono 2.37 hab24e00_0 conda-forge
font-ttf-inconsolata 3.000 h77eed37_0 conda-forge
font-ttf-source-code-pro 2.038 h77eed37_0 conda-forge
font-ttf-ubuntu 0.83 hab24e00_0 conda-forge
fontconfig 2.14.0 hc2a2eb6_1 conda-forge
fonts-conda-ecosystem 1 0 conda-forge
fonts-conda-forge 1 0 conda-forge
fonttools 4.37.4 py38h0a891b7_0 conda-forge
freetype 2.12.1 hca18f0e_0 conda-forge
freexl 1.0.6 h166bdaf_1 conda-forge
frozenlist 1.3.1 py38h0a891b7_0 conda-forge
fsspec 2022.8.2 pyhd8ed1ab_0 conda-forge
gdal 3.5.2 py38h721c686_1 conda-forge
geos 3.11.0 h27087fc_0 conda-forge
geotiff 1.7.1 h4fc65e6_3 conda-forge
gettext 0.19.8.1 h27087fc_1009 conda-forge
giflib 5.2.1 h36c2ea0_2 conda-forge
grpcio 1.43.0 py38h2457d08_0 conda-forge
h5py 3.7.0 nompi_py38h045baee_101 conda-forge
hdf4 4.2.15 h9772cbc_4 conda-forge
hdf5 1.12.2 nompi_h4df4325_100 conda-forge
heapdict 1.0.1 pypi_0 pypi
icu 70.1 h27087fc_0 conda-forge
identify 2.5.6 pyhd8ed1ab_0 conda-forge
idna 3.4 pyhd8ed1ab_0 conda-forge
imagecodecs 2022.9.26 py38h0e951e9_0 conda-forge
imageio 2.22.0 pyhfa7a67d_0 conda-forge
imagesize 1.4.1 pypi_0 pypi
importlib-metadata 4.11.4 py38h578d9bd_0 conda-forge
iniconfig 1.1.1 pyh9f0ad1d_0 conda-forge
jinja2 3.1.2 pypi_0 pypi
jmespath 1.0.1 pyhd8ed1ab_0 conda-forge
joblib 1.2.0 pyhd8ed1ab_0 conda-forge
jpeg 9e h166bdaf_2 conda-forge
json-c 0.16 hc379101_0 conda-forge
jxrlib 1.1 h7f98852_2 conda-forge
kealib 1.4.15 ha7026e8_1 conda-forge
keyutils 1.6.1 h166bdaf_0 conda-forge
kiwisolver 1.4.4 py38h43d8883_0 conda-forge
krb5 1.19.3 h08a2579_0 conda-forge
lcms2 2.12 hddcbb42_0 conda-forge
ld_impl_linux-64 2.38 h1181459_1 anaconda
lerc 4.0.0 h27087fc_0 conda-forge
libaec 1.0.6 h9c3ff4c_0 conda-forge
libavif 0.10.1 h5cdd6b5_2 conda-forge
libblas 3.9.0 16_linux64_openblas conda-forge
libbrotlicommon 1.0.9 h166bdaf_7 conda-forge
libbrotlidec 1.0.9 h166bdaf_7 conda-forge
libbrotlienc 1.0.9 h166bdaf_7 conda-forge
libcblas 3.9.0 16_linux64_openblas conda-forge
libcurl 7.85.0 h2283fc2_0 conda-forge
libdap4 3.20.6 hd7c4107_2 conda-forge
libdeflate 1.14 h166bdaf_0 conda-forge
libedit 3.1.20210910 h7f8727e_0 anaconda
libev 4.33 h516909a_1 conda-forge
libffi 3.4.2 h7f98852_5 conda-forge
libgcc-ng 12.1.0 h8d9b700_16 conda-forge
libgdal 3.5.2 h84f2e82_1 conda-forge
libgfortran-ng 12.1.0 h69a702a_16 conda-forge
libgfortran5 12.1.0 hdcd56e2_16 conda-forge
libglib 2.74.0 h7a41b64_0 conda-forge
libgomp 12.1.0 h8d9b700_16 conda-forge
libiconv 1.17 h166bdaf_0 conda-forge
libkml 1.3.0 h37653c0_1015 conda-forge
liblapack 3.9.0 16_linux64_openblas conda-forge
libllvm11 11.1.0 he0ac6c6_4 conda-forge
libnetcdf 4.8.1 nompi_h21705cb_104 conda-forge
libnghttp2 1.47.0 hff17c54_1 conda-forge
libnsl 2.0.0 h7f98852_0 conda-forge
libopenblas 0.3.21 pthreads_h78a6416_3 conda-forge
libpng 1.6.38 h753d276_0 conda-forge
libpq 14.5 he2d8382_0 conda-forge
libprotobuf 3.21.7 h6239696_0 conda-forge
librttopo 1.1.0 hf730bdb_11 conda-forge
libspatialite 5.0.1 hd36657c_19 conda-forge
libsqlite 3.39.4 h753d276_0 conda-forge
libssh2 1.10.0 hf14f497_3 conda-forge
libstdcxx-ng 12.1.0 ha89aaad_16 conda-forge
libtiff 4.4.0 h55922b4_4 conda-forge
libuuid 2.32.1 h7f98852_1000 conda-forge
libwebp-base 1.2.4 h166bdaf_0 conda-forge
libxcb 1.13 h7f98852_1004 conda-forge
libxml2 2.10.2 h4c7fe37_1 conda-forge
libxslt 1.1.35 h8affb1d_0 conda-forge
libzip 1.9.2 hc929e4a_1 conda-forge
libzlib 1.2.12 h166bdaf_4 conda-forge
libzopfli 1.0.3 h9c3ff4c_0 conda-forge
lightgbm 3.3.2 py38h709712a_0 conda-forge
llvmlite 0.39.1 py38h38d86a4_0 conda-forge
locket 1.0.0 pyhd8ed1ab_0 conda-forge
lxml 4.9.1 py38h0a891b7_0 conda-forge
lz4-c 1.9.3 h9c3ff4c_1 conda-forge
markupsafe 2.1.1 pypi_0 pypi
marshmallow 3.18.0 pyhd8ed1ab_0 conda-forge
marshmallow-enum 1.5.1 pyh9f0ad1d_3 conda-forge
matplotlib-base 3.5.3 py38h38b5ce0_2 conda-forge
msgpack-python 1.0.4 py38h43d8883_0 conda-forge
multipledispatch 0.6.0 py_0 conda-forge
munch 2.5.0 py_0 conda-forge
munkres 1.1.4 pyh9f0ad1d_0 conda-forge
mypy_extensions 0.4.3 py38h578d9bd_5 conda-forge
ncurses 6.3 h27087fc_1 conda-forge
netcdf-fortran 4.6.0 nompi_hc402ea5_101 conda-forge
netcdf4 1.6.0 nompi_py38h32db9c8_101 conda-forge
networkx 2.8.7 pyhd8ed1ab_0 conda-forge
nodeenv 1.7.0 pyhd8ed1ab_0 conda-forge
nspr 4.33 h295c915_0 anaconda
nss 3.78 h2350873_0 conda-forge
numba 0.56.2 py38h9a4aae9_1 conda-forge
numpy 1.23.2 py38h3a7f9d9_0 conda-forge
oauthlib 3.2.1 pyhd8ed1ab_0 conda-forge
openjpeg 2.5.0 h7d73246_1 conda-forge
openssl 3.0.5 h166bdaf_2 conda-forge
packaging 21.3 pyhd8ed1ab_0 conda-forge
pandas 1.4.3 py38h47df419_0 conda-forge
param 1.12.2 pyh6c4a22f_0 conda-forge
partd 1.3.0 pyhd8ed1ab_0 conda-forge
patsy 0.5.2 pyhd8ed1ab_0 conda-forge
pcre 8.45 h9c3ff4c_0 conda-forge
pcre2 10.37 hc3806b6_1 conda-forge
pillow 8.4.0 pypi_0 pypi
pip 22.2.2 pyhd8ed1ab_0 conda-forge
pixman 0.40.0 h36c2ea0_0 conda-forge
platformdirs 2.5.2 pyhd8ed1ab_1 conda-forge
plotly 5.10.0 pyhd8ed1ab_0 conda-forge
pluggy 1.0.0 py38h578d9bd_3 conda-forge
pooch 1.6.0 pyhd8ed1ab_0 conda-forge
poppler 22.04.0 h0733791_3 conda-forge
poppler-data 0.4.11 hd8ed1ab_0 conda-forge
postgresql 14.5 ha7cec9f_0 conda-forge
pre-commit 2.20.0 py38h578d9bd_0 conda-forge
proj 9.0.1 h93bde94_1 conda-forge
protobuf 4.21.7 py38hfa26641_0 conda-forge
psutil 5.9.1 py38h0a891b7_0 conda-forge
pthread-stubs 0.4 h36c2ea0_1001 conda-forge
pvlib 0.9.2 pyha770c72_2 conda-forge
pvlib-python 0.9.2 hd8ed1ab_2 conda-forge
py 1.11.0 pyh6c4a22f_0 conda-forge
pycparser 2.21 pyhd8ed1ab_0 conda-forge
pyct 0.4.8 py38h06a4308_1 anaconda
pydata-sphinx-theme 0.9.0 pypi_0 pypi
pygments 2.13.0 pypi_0 pypi
pyhdf 0.10.5 py38hd2cc768_0 conda-forge
pyjwt 2.5.0 pyhd8ed1ab_0 conda-forge
pyopenssl 22.0.0 pyhd8ed1ab_1 conda-forge
pyparsing 3.0.9 pyhd8ed1ab_0 conda-forge
pyproj 3.3.1 py38he1635e7_1 conda-forge
pysocks 1.7.1 pyha2e5f31_6 conda-forge
pytest 7.1.2 py38h578d9bd_0 conda-forge
python 3.8.13 ha86cf86_0_cpython conda-forge
python-dateutil 2.8.2 pyhd8ed1ab_0 conda-forge
python_abi 3.8 2_cp38 conda-forge
pytz 2022.4 pyhd8ed1ab_0 conda-forge
pywavelets 1.3.0 py38h71d37f0_1 conda-forge
pyyaml 6.0 py38h0a891b7_4 conda-forge
rasterio 1.3.2 py38h164e37e_0 conda-forge
ray-core 1.12.1 py38hb9c8dfe_0 conda-forge
readline 8.1.2 h0f457ee_0 conda-forge
requests 2.28.1 pyhd8ed1ab_1 conda-forge
requests-oauthlib 1.3.1 pyhd8ed1ab_0 conda-forge
rioxarray 0.12.0 pyhd8ed1ab_0 conda-forge
s2cloudless 1.5.0 pyhd8ed1ab_0 conda-forge
s3transfer 0.6.0 pyhd8ed1ab_0 conda-forge
scikit-image 0.19.3 py38h47df419_1 conda-forge
scikit-learn 1.1.2 py38h0b08f9b_0 conda-forge
scipy 1.9.0 py38hea3f02b_0 conda-forge
sentinelhub 3.4.4 pyhd8ed1ab_0 conda-forge
setproctitle 1.2.2 py38h0a891b7_2 conda-forge
setuptools 65.4.1 pyhd8ed1ab_0 conda-forge
shapely 1.8.4 py38h3b45516_0 conda-forge
sisppeo 1.3.0 pypi_0 pypi
six 1.16.0 pyh6c4a22f_0 conda-forge
snappy 1.1.9 hbd366e4_1 conda-forge
snowballstemmer 2.2.0 pypi_0 pypi
snuggs 1.4.7 py_0 conda-forge
sortedcontainers 2.4.0 pypi_0 pypi
soupsieve 2.3.2.post1 pypi_0 pypi
sparse 0.13.0 pyhd8ed1ab_0 conda-forge
sphinx 4.5.0 pypi_0 pypi
sphinx-copybutton 0.5.0 pypi_0 pypi
sphinx-panels 0.6.0 pypi_0 pypi
sphinxcontrib-applehelp 1.0.2 pypi_0 pypi
sphinxcontrib-devhelp 1.0.2 pypi_0 pypi
sphinxcontrib-htmlhelp 2.0.0 pypi_0 pypi
sphinxcontrib-jsmath 1.0.1 pypi_0 pypi
sphinxcontrib-qthelp 1.0.3 pypi_0 pypi
sphinxcontrib-serializinghtml 1.1.5 pypi_0 pypi
sqlite 3.39.4 h4ff8645_0 conda-forge
statsmodels 0.13.2 py38h71d37f0_0 conda-forge
stringcase 1.2.0 py_0 conda-forge
tblib 1.7.0 pypi_0 pypi
tenacity 8.1.0 pyhd8ed1ab_0 conda-forge
threadpoolctl 3.1.0 pyh8a188c0_0 conda-forge
tifffile 2022.8.12 pyhd8ed1ab_0 conda-forge
tiledb 2.11.3 h3f4058f_0 conda-forge
tk 8.6.12 h27826a3_0 conda-forge
toml 0.10.2 pyhd8ed1ab_0 conda-forge
tomli 2.0.1 pyhd8ed1ab_0 conda-forge
toolz 0.12.0 pyhd8ed1ab_0 conda-forge
tornado 6.1 pypi_0 pypi
tqdm 4.64.0 pyhd8ed1ab_0 conda-forge
typing_extensions 4.3.0 pyha770c72_0 conda-forge
typing_inspect 0.7.1 pyh6c4a22f_0 conda-forge
tzcode 2022d h166bdaf_0 conda-forge
tzdata 2022d h191b570_0 conda-forge
ukkonen 1.0.1 py38h43d8883_2 conda-forge
unicodedata2 14.0.0 py38h0a891b7_1 conda-forge
urllib3 1.26.11 pyhd8ed1ab_0 conda-forge
utm 0.7.0 pyhd8ed1ab_0 conda-forge
virtualenv 20.16.5 py38h578d9bd_0 conda-forge
wheel 0.37.1 pyhd8ed1ab_0 conda-forge
xarray 2022.6.0 pyhd8ed1ab_1 conda-forge
xerces-c 3.2.3 h55805fa_5 conda-forge
xesmf 0.6.3 pyhd8ed1ab_1 conda-forge
xorg-kbproto 1.0.7 h7f98852_1002 conda-forge
xorg-libice 1.0.10 h7f98852_0 conda-forge
xorg-libsm 1.2.3 hd9c2040_1000 conda-forge
xorg-libx11 1.7.2 h7f98852_0 conda-forge
xorg-libxau 1.0.9 h7f98852_0 conda-forge
xorg-libxdmcp 1.1.3 h7f98852_0 conda-forge
xorg-libxext 1.3.4 h7f98852_1 conda-forge
xorg-libxrender 0.9.10 h7f98852_1003 conda-forge
xorg-renderproto 0.11.1 h7f98852_1002 conda-forge
xorg-xextproto 7.3.0 h7f98852_1002 conda-forge
xorg-xproto 7.0.31 h7f98852_1007 conda-forge
xz 5.2.6 h166bdaf_0 conda-forge
yaml 0.2.5 h7f98852_2 conda-forge
zfp 1.0.0 h27087fc_1 conda-forge
zict 2.2.0 pypi_0 pypi
zipp 3.8.1 pyhd8ed1ab_0 conda-forge
zlib 1.2.12 h166bdaf_4 conda-forge
zlib-ng 2.0.6 h166bdaf_0 conda-forge
zstd 1.5.2 h6239696_4 conda-forge

```

**ISSUE**

_Description of the problem_

I use of set of functions (which I simplified a lot and detailed below after traceback) to extract and transform some data into an xarray Dataset.  
I have 3 functions which i’ll call A, B and C:

```python

def A(**kwargs):
    ray_init(input_products)

    # make None parameters lists of same size as Input_products from kwargs

    futures = []
    for kwarg in zip(**kwargs):
        futures.append(B.remote(**copy.copy(kwargs)))

    res = ray_get(futures, 'A')

    if save:
        # produce filename then save
    return res

@ray.remote
def B(**kwargs):
    # tweak config from kwargs
    return C( **kwargs,** config)

def C(**kwargs):
    builder = ProductBuilder()
    # processing steps calls from builder class
    products = builder.get_products()

    if save:
       # produce filename then save
    return products

```

- Function A initialize ray (shutdown if initalized then init with correct number of cpus) , then produces the futures list (append B.remote(\*\*kwargs)) and finally retrieve the results with ray\_get (custom function detailed after traceback)
- Function B do some tweaking to a configuration dictionnary then call function C
- Function C do the real work then returns the result

What makes me reallt think that this is a Ray problem is that up to the return of the result (last line of function C), everything goes well (I tested it with prints an debugger). But, as soon as I try to retrieve the result with `yield ray.get(done)` (in function ray\_get) in the next line of function A (so the returns of function C and B are ok) I get the following error message:

_Error message (simplified)_

```auto
=> call to custom ray_get function (detailed below)
==> result = [_ for _ in tqdm(to_generator(futures), in ray_get
==> result = [_ for _ in tqdm(to_generator(futures), in <listcomp>
==> tqdm/std.py", line 1195, in __iter__
           for obj in iterable:
==> yield ray.get(done) in to_generator
==> ray/_private/client_mode_hook.py", line 105, in wrapper
           return func(*args, **kwargs)
==> ray/worker.py", line 1811, in get
          raise value
ray.exceptions.RaySystemError: System error: can't set attribute
traceback: Traceback (most recent call last):
==> ray/serialization.py", line 332, in deserialize_objects
           obj = self._deserialize_object(data, metadata, object_ref)
==> ray/serialization.py", line 235, in _deserialize_object
           return self._deserialize_msgpack_data(data, metadata_fields)
==> ray/serialization.py", line 190, in _deserialize_msgpack_data
           python_objects = self._deserialize_pickle5_data(pickle5_data)
==> ray/serialization.py", line 178, in _deserialize_pickle5_data
           obj = pickle.loads(in_band, buffers=buffers)
AttributeError: can't set attribute

```

I tried to look for this error message in `ray`’s and `pickle`’s source code but could not find it. Also I tried to debug my program with pycharm’s debugger but since Objectref is obfuscated i couldn’t go further this way either.

Thus I’m asking in this forum the following:

- I don’t know what the cause of this error can be
- Error message should be clearer

```python
def ray_init(iterable: Sized):
    """Get the number of available CPUs from any sized object."""
    num_cpus = psutil.cpu_count(logical=False)
    cpus = [psutil.cpu_count(logical=False), len(iterable), num_cpus]
    num_cpus = min(val for val in cpus if val is not None)
    if ray.is_initialized():
        ray.shutdown()
    ray.init(num_cpus=num_cpus)

def ray_get(futures: list, msg: str = 'example') -> list:
    """Process ray futures with a progress bar."""
    def to_generator(remaining):
        while remaining:
            done, remaining = ray.wait(remaining)
            yield ray.get(done)
    result = [_ for _ in tqdm(to_generator(futures),
                              total=len(futures),
                              desc=f'Processing {msg}',
                              position=0)]
    ray.shutdown()
    return result

```

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<div class="post-metadata">

**Author:** ![Stephanie\_Wang](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/stephanie_wang/32/18_2.png) [@Stephanie\_Wang](https://discuss.ray.io/u/Stephanie_Wang)\
**Post date:** [January 17, 2023, 4:27pm UTC](https://discuss.ray.io/t/attributeerror-cant-set-atttribute/8985/2 "2023-01-17T16:27:29Z")

</div>

Hmm I’m not sure off the top of my head about the root cause either, but let’s try to debug it, and you’re definitely right that this error message could be vastly improved.

First off, are you using Ray Client? Could you try without and see if you get the same error? Also wondering if you can provide a minimal reproducible example that I can run?

---

<div class="post-metadata">

**Author:** ![pierre-manchon](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/pierre-manchon/32/3729_2.png) [@pierre-manchon](https://discuss.ray.io/u/pierre-manchon)\
**Post date:** [January 17, 2023, 5:15pm UTC](https://discuss.ray.io/t/attributeerror-cant-set-atttribute/8985/3 "2023-01-17T17:15:19Z")

</div>

Good evening!

I’m not really sure if I’m using ray client or not, I installed it with conda (`ray-core` in my environment.yaml) and didn’t modify any configuration, just sent remote methods to the futures list and did ray.get from that on.

Also I did more research today using the debugger to understand what happens and where the error could originate:

- In ray the error happens precisely at [this line](https://github.com/ray-project/ray/blob/b233222611a81fcf0e4ddaaf49de808cfa23a388/python/ray/_private/serialization.py#L195).
- I then dug a little more through pickle and found that:
  - I can successfully load my `in_band` and `buffers` parameters into the [`_Unpickler` class](https://github.com/python/cpython/blob/main/Lib/pickle.py#L1129).
  - I can’t call the [`load` method](https://github.com/python/cpython/blob/main/Lib/pickle.py#L1179) because it returns the same error that I get when running my program as usual

It seems to me that [this piece of code](https://github.com/python/cpython/blob/main/Lib/pickle.py#L1199-L1207) is what is causing the error (confirmed by the fact that if I run the `load` method a second time (manually) I get an EOF error which is raised in case there is no key.

My guess is that a key is found but is different than the keys from dispatch thus the attribute can’t be set.  
What I still don’t get is how the data could “go this far in the functions and methods” for it to raise an error like that

Thank you for your time,  
Pierre

---

<div class="post-metadata">

**Author:** ![Stephanie\_Wang](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/stephanie_wang/32/18_2.png) [@Stephanie\_Wang](https://discuss.ray.io/u/Stephanie_Wang)\
**Post date:** [January 18, 2023, 1:18am UTC](https://discuss.ray.io/t/attributeerror-cant-set-atttribute/8985/4 "2023-01-18T01:18:08Z")

</div>

Hmm I’m not sure either but it seems likely to be a bug. It would be helpful if you could provide a reproducible example and file an issue on GitHub. We can follow up there. Thanks!

---

<div class="post-metadata">

**Author:** ![pierre-manchon](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/pierre-manchon/32/3729_2.png) [@pierre-manchon](https://discuss.ray.io/u/pierre-manchon)\
**Post date:** [January 23, 2023, 4:45pm UTC](https://discuss.ray.io/t/attributeerror-cant-set-atttribute/8985/5 "2023-01-23T16:45:36Z")

</div>

Good evening Stéphanie,

I found the source of the error in my code:

In my function C, I use a ProductBuilder class to call other classes (call them X, Y, Z). Each of X, Y and Z are subclassed by a mixin class (call it M). The error was that M had non empty slots with multiple values.  
The fix is to simply delete every other value except ‘dataset’ (which is used everywhere for the processing) M.

I still can’t produce a reproducible example yet but as soon as I’ll be able to, I will get back to you

Pierre

---

<div class="post-metadata">

**Author:** ![Stephanie\_Wang](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/stephanie_wang/32/18_2.png) [@Stephanie\_Wang](https://discuss.ray.io/u/Stephanie_Wang)\
**Post date:** [January 23, 2023, 4:58pm UTC](https://discuss.ray.io/t/attributeerror-cant-set-atttribute/8985/6 "2023-01-23T16:58:50Z")

</div>

I see, thanks! Definitely let me know if you can find a reproducible example; it’d be great to improve this (awful) debugging experience 🙂