Unable to get default parameters of STL function

[Ashish-Tiger]

Describe the bug

I am trying to get default argument of the SYL function but unable to get the saem. Also, it doesnt seem there is anything called "text__signature" which can be used by inspect library to get a signature of the init.

Code Sample, a copy-pastable example if possible

import statsmodels.tsa.seasonal.STL
import inspect 
inspect.signature(STL.__init__)
# <Signature (self, /, *args, **kwargs)>

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Expected Output

expect output:

<Signature (self, endog, period=None, seasonal=7, trend=None, low_pass=None,
        seasonal_deg=1, trend_deg=1, low_pass_deg=1, robust=False,
        seasonal_jump=1, trend_jump=1, low_pass_jump=1)

Output of import statsmodels.api as sm; sm.show_versions()

[paste the output of import statsmodels.api as sm; sm.show_versions() here below this line]

INSTALLED VERSIONS

Python: 3.10.8.final.0
OS: Linux 5.10.102.1-microsoft-standard-WSL2 #1 SMP Wed Mar 2 00:30:59 UTC 2022 x86_64
byteorder: little
LC_ALL: None
LANG: C.UTF-8

statsmodels

Installed: 0.13.5 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/statsmodels)

Required Dependencies

cython: Not installed
numpy: 1.23.5 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/numpy)
scipy: 1.10.0 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/scipy)
pandas: 1.5.2 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/pandas)
dateutil: 2.8.2 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/dateutil)
patsy: 0.5.3 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/patsy)

Optional Dependencies

matplotlib: 3.6.2 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/matplotlib)
backend: module://matplotlib_inline.backend_inline
cvxopt: Not installed
joblib: 1.2.0 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/joblib)

Developer Tools

IPython: 8.8.0 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/IPython)
jinja2: 3.1.2 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/jinja2)
sphinx: Not installed
pygments: 2.14.0 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/pygments)
pytest: 7.1.2 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/pytest)
virtualenv: 20.17.1 (/home/user1/miniconda3/envs/ADT/lib/python3.10/site-packages/virtualenv)

[bashtage]

This is a limitation of Cython code I believe. Not sure there is much we can do about it. Might be possible to use bindings to populate the signature, but I think it still won't get defaults.

[Ashish-Tiger]

@bashtage Yes, I read about this particular binding binding (True / False) option.

Compiler directives¶

Stackoverflow link:
https://stackoverflow.com/questions/46033277/how-to-introspect-a-function-defined-in-a-cython-c-extension-module

Just trying to understand if there is a way to implement this?