Problem with Matplotlib example

[Martin Schöön]

Anyone had success running this example?
https://tinyurl.com/yhhyc9r

When I try I get this error:
"TypeError: __init__() got an unexpected keyword argument 'transform'"

This is for the line
"    m = MarkerStyle(SUCESS_SYMBOLS[mood], transform=t)"

Yes, I know, I could dive into the documentation myself but I hope
some kind soul here will help out.

As far as I know I have an up-to-date matplotlib installed. Pip has
nothing more modern to offer me.

TIA

/Martin