AttributeError when not trying to use any attribute - python-3.x

Question

Good morning!
I'm using a code (with python 3.8) that is running both in a local PC and in a ssh server. In one point, I'm loading data from a pickle using the next piece of code:
from os.path import exists
import _pickle as pickle
def load_pickle(pickle_file):
if exists(pickle_file):
with open(pickle_file, 'rb') as f:
loaded_dic = pickle.load(f)
return loaded_dic
else:
return 'Pickle not found'
pickle_file is a string with the path of the pickle. If the pickle exists, the function returns a dictionary, while if it doesn't exist, it returns the string 'Pickle not found'.
In my local PC, the code works perfectly, loading the dict without problems. However, in the ssh server, theoretically, the dict is loaded, but, if I try to access to it, jus typing loaded_dic, it throws the following error:
AttributeError: 'NoneType' object has no attribute 'axes'
Due to it, the rest of my code fails when it try to use the variable loaded_dic.
Thank you very much in advance!

Answer 1

I have a similar problem. For me it happens as I store pandas DataFrames in a dictionary and save this dict as a pickle with pandas version '1.1.1'.
When I read the dictionary pickle with pandas version '0.25.3' on another server, I get the same error.
Both have pickle version 4.0 and I do not have a solution yet, other than upgrading to similar pandas versions.
I made a small example, it also happens when I store just a DataFrame, Saving it on one machine:
import pandas as pd
print("Pandas version", pd.__version__)
df = pd.DataFrame([1, 2, 3])
df.to_pickle('df.pkl')
Pandas version 1.1.1
Then loading it on another machine:
import pandas as pd
print("Pandas version", pd.__version__)
df = pd.read_pickle('df.pkl')
print(type(df))
Pandas version 0.25.3
<class 'pandas.core.frame.DataFrame'>
print(len(df))
results in this error:
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-8-9f6b6d8c3cd3> in <module>
----> 1 print(len(df))
/opt/conda/lib/python3.7/site-packages/pandas/core/frame.py in __len__(self)
994 Returns length of info axis, but here we use the index.
995 """
--> 996 return len(self.index)
997
998 def dot(self, other):
/opt/conda/lib/python3.7/site-packages/pandas/core/generic.py in __getattr__(self, name)
5173 or name in self._accessors
5174 ):
-> 5175 return object.__getattribute__(self, name)
5176 else:
5177 if self._info_axis._can_hold_identifiers_and_holds_name(name):
pandas/_libs/properties.pyx in pandas._libs.properties.AxisProperty.__get__()
AttributeError: 'NoneType' object has no attribute 'axes'

Answer 2

Avi's answer helped me. I had pickled with a later version of Pandas and was trying to read the pickle file with an earlier version.

Answer 3

This code clearly doesn't work anywhere; it doesn't return loaded_dict, a local variable, so nothing can use it. Change it to:
return pickle.load(f)
and the caller will receive the loaded dict instead of the default return value, None.
Update for edited question: With the return, your code works as written. Your pickle file on said machine must have the result of pickling None stored in it, rather than whatever you expected. Or your code is broken in some other place we haven't seen. The loading code is fine, and behaving exactly as its supposed to.