BUG: Support keywords in pd.Timestamp.isoformat(), ref.#26131 is stale.

[boringow]

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

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

• (optional) I have confirmed this bug exists on the master branch of pandas.

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Note: Please read this guide detailing how to provide the necessary information for us to reproduce your bug.

import pandas as pd
now=pd.Timestamp.utcnow()
now.isoformat(timespec="milliseconds")
print(now)

Problem description

The isoformat is just to follow the ISO format 8601, but it is not detecting any keywords.

Expected Output

"2020-02-03 21:54:34:024"

Output of pd.show_versions()

INSTALLED VERSIONS

commit : 9d598a5
python : 3.8.2.final.0
python-bits : 32
OS : Windows
OS-release : 10
Version : 10.0.19041
machine : AMD64
processor : Intel64 Family 6 Model 78 Stepping 3, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : es_ES.cp1252

pandas : 1.2.1
numpy : 1.20.0
pytz : 2021.1
dateutil : 2.8.1
pip : 20.3.1
setuptools : 51.0.0
Cython : None
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : None
IPython : None
pandas_datareader: None
bs4 : None
bottleneck : None
fsspec : None
fastparquet : None
gcsfs : None
matplotlib : None
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : None
pyxlsb : None
s3fs : None
scipy : None
sqlalchemy : None
tables : None
tabulate : None
xarray : None
xlrd : None
xlwt : None
numba : None

[phofl]

Hi, what do you expect here? This is exactly the same as #26131

[boringow]

Yeah, but the issue #26131 is stale and still not fixed.

[boringow]

@jreback told me to open a new PR, as I am having the same issue.

[phofl]

PR is Pull Request not Issue?

The PR is stale not the issue

[boringow]

Oh sorry. I did not know what PR was. I am really trying to help in here but as I am new everyone looks really busy. I will pull a new PR request now 👍

[phofl]

Closing then