BUG: Period.now() does not accept kwarg "freq" but doc and typing say otherwise

[tscheburaschka]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

import pandas as pd
p = pd.Period.now(freq='D')

# Gives: "TypeError: Period.now() takes no keyword arguments"

p = pd.Period.now('D')  
# Gives: Period('2023-05-24', 'D')
# BTW, here the type checker complains about wrong type, expects 'BaseOffset' not 'str'

Issue Description

The method call Period.now(freq="D") raises a "TypeError: Period.now() takes no keyword arguments" but this behavior deviates from Pandas 1.5.X and is in contradiction to type annotations and not documented.

Expected Behavior

The kwarg "freq" should work or it should be documented accordingly in type annotations and as breaking change.

Installed Versions

INSTALLED VERSIONS

commit : 37ea63d
python : 3.11.3.final.0
python-bits : 64
OS : Windows
OS-release : 10
Version : 10.0.14393
machine : AMD64
processor : Intel64 Family 6 Model 85 Stepping 0, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : de_DE.cp1252

pandas : 2.0.1
numpy : 1.24.3
pytz : 2023.3
dateutil : 2.8.2
setuptools : 67.8.0
pip : 23.1.2
Cython : None
pytest : 7.3.1
hypothesis : 6.75.3
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : 2.9.6
jinja2 : None
IPython : None
pandas_datareader: None
bs4 : 4.12.2
bottleneck : None
brotli : None
fastparquet : None
fsspec : None
gcsfs : None
matplotlib : None
numba : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : 10.0.1
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : None
snappy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
zstandard : None
tzdata : 2023.3
qtpy : None
pyqt5 : None

[lithomas1]

Hi,
Thanks for reporting this issue.

The issue is with the passing of freq as a keyword style. This function is defined in our Cython code, and by default that doesn't support single arguments passed in in keyword style (for perf reasons? cython/cython#3090).

>>> import pandas as pd
>>> pd.Period.now("D")
Period('2023-05-24', 'D')

This is a bug on our end, and it looks like the fix is to set the always_allow_keywords directive in Cython to true.

I'll try to submit a patch in the next few days.

[tscheburaschka]

As far as my limited understanding goes, the default for always_allow_keywords was set to true a few years ago (see cython/cython#3605) but maybe this is overriden in pandas.

[lithomas1]

Sadly, that's a Cython 3 only change. We are on one of the 0.29 releases.
(Cython 3 is the next major version of Cython. It should come out soon sometime.)

[tscheburaschka]

I can see, that the associated PR is hanging. Any chances this can be fixed in the next release?
(Just asking, because otherwise I would implement a workaround in my application code.)

[lithomas1]

I've hit a Cython bug I think
cython/cython#5484.

This is probably going to take a while.

[tscheburaschka]

Thank you for your quick reply. Helps me, to take a decision.