Great fan of the pystata addition to Stata17 for .ipynb

However, I am a bit irritated by the fact that single '%' does not support arguments to commands like the double '%%' cell magic does.
E.g.

%stata -d myDataFrame

throws r(199):
- is not a valid command name., whilst

%%
stata -d myDataFrame

works perfectly fine.
What's the reason behind this?