Isn’t it just 
I don’t think Trinket has updated their skulpt implementation for a while. skulpt.org might be a better place to check a few lines of code as that’s usually up to date. But while anvil tries to stay inline with skulpt we may at times be ahead or behind the project or differ at the edges. So it’s not always like for like.
For example anvil has the {**my_dict} syntax available where this is in the queue in skulpt.
You can also open up a module in anvil and run the script as the startup form. Some print statements will probably determine what you want.