ERROR: Axes instance argument was not found in a figure

[Pikachu233]

Hello,

When I try to generate the paga comparison plot using the code in https://nbviewer.jupyter.org/github/theislab/paga/blob/master/blood/dahlin18/dahlin18.ipynb In [50]

I got the following error:

---

ValueError Traceback (most recent call last)
in
----> 1 pl.sca(axs[0])
2 pl.xlabel('')
3 pl.ylabel('')
4 axs[0].set_frame_on(False)
5 pl.savefig('./gast44hr.pdf')

/anaconda3/lib/python3.7/site-packages/matplotlib/pyplot.py in sca(ax)
912 m.canvas.figure.sca(ax)
913 return
--> 914 raise ValueError("Axes instance argument was not found in a figure")
915
916

ValueError: Axes instance argument was not found in a figure

Before this code block, everything else works perfectly fine, but I could not find why the axes setting going wrong. Sincerely hope someone could offer some suggestions. Thanks!