Repository: evidentlyai/evidently
Issue: Calculations Not Found + Custom Statistical Tests
Root cause: Documentation Deficiency

Hi guys,

Wondering if you could help me out with an issue I'm having. I've been following the tutorial for creating custom statistical tests, however I'm unable to import evidently.calculations. I've posted snippets of my code below and versions, and can provide more info if needed.

```
evidently version: 0.1.56.dev0
Python version: 3.9.13
Intel Mac
```

Running a traceback on `python from evidently.calculations.stattests import StatTest` gives:

```
Traceback (most recent call last):
  File "/var/folders/6k/ht2ztk914gj6wy4933nd73v80000gn/T/ipykernel_61124/1582639923.py", line 3, in <cell line: 2>
    from evidently.calculations.stattests import StatTest
ModuleNotFoundError: No module named 'evidently.calculations'
```

I installed evidently using `pipenv install evidently`, when trying to reinstall though I get the following error when uninstalling:

```cmd
AttributeError: module 'typing' has no attribute '_ClassVar'
```

Any help or pointers in the right direction would be appreciated.

Thanks!

Full list of packages installed for context below:
```cmd
Package                       Version
----------------------------- -----------
appnope                       0.1.3
asttokens                     2.0.8
backcall                      0.2.0
black                         22.8.0
cachetools                    5.2.0
certifi                       2022.6.15
charset-normalizer            2.1.1
click                         8.1.3
colorlog                      6.7.0
dataclasses                   0.6
db-dtypes                     1.0.3
debugpy                       1.6.3
decorator                     5.1.1
entrypoints                   0.4
evidently                     0.1.56.dev0
executing                     1.0.0
google-api-core               2.10.0
google-auth                   2.11.0
google-auth-oauthlib          0.5.2
google-cloud-bigquery         3.3.2
google-cloud-bigquery-storage 2.14.2
google-cloud-core             2.3.2
google-crc32c                 1.5.0
google-resumable-media        2.3.3
googleapis-common-protos      1.56.4
grpcio                        1.48.1
grpcio-status                 1.48.1
idna                          3.3
ipykernel                     6.15.2
ipython                       8.4.0
jedi                          0.18.1
joblib                        1.1.0
jupyter_client                7.3.5
jupyter-core                  4.11.1
matplotlib-inline             0.1.6
mypy-extensions               0.4.3
nest-asyncio                  1.5.5
numpy                         1.23.2
oauthlib                      3.2.0
packaging                     21.3
pandas                        1.4.4
pandas-gbq                    0.17.8
parso                         0.8.3
pathspec                      0.10.1
patsy                         0.5.2
pexpect                       4.8.0
pickleshare                   0.7.5
pip                           22.2.2
platformdirs                  2.5.2
plotly                        5.10.0
prompt-toolkit                3.0.31
proto-plus                    1.22.1
protobuf                      4.21.5
psutil                        5.9.2
ptyprocess                    0.7.0
pure-eval                     0.2.2
pyarrow                       9.0.0
pyasn1                        0.4.8
pyasn1-modules                0.2.8
pydata-google-auth            1.4.0
Pygments                      2.13.0
pyparsing                     3.0.9
python-dateutil               2.8.2
pytz                          2022.2.1
PyYAML                        5.4.1
pyzmq                         23.2.1
requests                      2.28.1
requests-oauthlib             1.3.1
rsa                           4.9
scikit-learn                  1.1.2
scipy                         1.9.1
setuptools                    63.4.3
six                           1.16.0
stack-data                    0.5.0
statsmodels                   0.13.2
tenacity                      8.0.1
threadpoolctl                 3.1.0
tomli                         2.0.1
tornado                       6.2
traitlets                     5.3.0
typing_extensions             4.3.0
urllib3                       1.26.12
wcwidth                       0.2.5
wheel                         0.37.1
```

Hi!

Calculations were moved to a separate module in the last release, but examples were updated with this change a little bit earlier.

You can try to upgrade `evidently` library with `pip install evidently==0.1.57.dev0 --upgrade` the example should work with it.

Great - that did the job! Thanks for getting back to me.