Issue with empty UMAP Plot in SnapATAC2 (v2.9.0)

[yellowlemon8]

Hi Kai,

Thanks for developing SnapATAC2!
I encountered an issue when plotting UMAP using version 2.9.0.
Environment:
snap.version = 2.9.0

Code:
`import matplotlib.pyplot as plt

snap.pl.umap(data, color="sample")
plt.show()`

Issue:
The output figure is empty (see attached screenshot).
Question:
Could this be related to my environment or am I missing a required step before plotting?

Thanks for your help!