ValueError: subformat not allowed for format jyear_str in Example

When running this code:

from poliastro.examples import molniya

molniya.plot()

I get this error:

WARNING: AstropyDeprecationWarning: The private astropy._erfa module has been made into its own package, pyerfa, which is a dependency of astropy and can be imported directly using "import erfa" [astropy._erfa]
Traceback (most recent call last):
  File ".\planetSim.py", line 3, in <module>
    molniya.plot()
  File "C:\Users\####\AppData\Local\Programs\Python\Python38\lib\site-packages\poliastro\twobody\orbit.py", line 1435, in plot
    return StaticOrbitPlotter().plot(self, label=label)
  File "C:\Users\####\AppData\Local\Programs\Python\Python38\lib\site-packages\poliastro\plotting\static.py", line 215, in plot
    lines = self._plot(orbit, label=label, color=color, trail=trail)
  File "C:\Users\####\AppData\Local\Programs\Python\Python38\lib\site-packages\poliastro\plotting\_base.py", line 153, in _plot
    label = generate_label(orbit.epoch, label)
  File "C:\Users\####\AppData\Local\Programs\Python\Python38\lib\site-packages\poliastro\plotting\util.py", line 20, in generate_label
    epoch.out_subfmt = "date_hm"
  File "C:\Users\####\AppData\Local\Programs\Python\Python38\lib\site-packages\astropy\time\core.py", line 622, in out_subfmt
    self._time.out_subfmt = val
  File "C:\Users\####\AppData\Local\Programs\Python\Python38\lib\site-packages\astropy\time\formats.py", line 183, in out_subfmt
    self._select_subfmts(subfmt)
  File "C:\Users\####\AppData\Local\Programs\Python\Python38\lib\site-packages\astropy\time\formats.py", line 396, in _select_subfmts
    raise ValueError(f'subformat not allowed for format {cls.name}')
ValueError: subformat not allowed for format jyear_str

(I replaced my Username with ####)

(I dont use conda for this project)

• pip freeze:

# Paste your output here:
`astropy==4.2
astroquery==0.4.1
beautifulsoup4==4.9.3
certifi==2020.12.5
chardet==4.0.0
cycler==0.10.0
html5lib==1.1
idna==2.10
jplephem==2.15
keyring==22.0.0
kiwisolver==1.3.1
llvmlite==0.35.0
matplotlib==3.3.3
numba==0.52.0
numpy==1.19.5
pandas==1.2.1
Pillow==8.1.0
plotly==4.14.3
poliastro==0.14.0
pyerfa==1.7.1.1
pyparsing==2.4.7
python-dateutil==2.8.1
pytz==2020.5
pywin32-ctypes==0.2.0
requests==2.25.1
retrying==1.3.3
scipy==1.6.0
six==1.15.0
soupsieve==2.1
urllib3==1.26.2
webencodings==0.5.1`

[X52p]

Thanks! Downgrading to 4.0 fixed it.

[cosmocaos]

Thanks for yesterday’s help @DhruvSondhi and @Yash-10. It seems that if poliastro is imported first, then astropy version 4.0 is imported, otherwise astropy 4.2 is imported and it is necessesary to reset the virtualenv.