Then you write one short operator (and I agree that some static languages make this more cumbersome than it should be) to say so, and either handle the case where it isn't, or explicitly declare yourself partial and not handling it.
> Also, how do you then access nested objects, like data['key'][0]['attr'] in Python?
With lenses, something like:
data ^? (key "key") >>> (nth 0) >>> (key "attr")
If you do several unsafe operations in a row then this is cumbersome by design - you want to be clear which parts of your program are safe and which are unsafe, so that readers can understand and know where to review. But a good language should let you compose together several unsafe operations in a lightweight way and then execute them as a single unsafe operation, for cases like this where you want to work in the unsafe part of the language for a bit.
But my main point is that HideousKojima's "statically-typed" solution would result in a runtime type error if it was given unexpected input, just like a dynamically typed solution.
> But my main point is that HideousKojima's "statically-typed" solution would result in a runtime type error if it was given unexpected input, just like a dynamically typed solution.
I don't think HideousKojima ever called it a "statically-typed solution". Their point was that statically-typed languages still let you write unchecked code when you want to - and yes, of course such unchecked code can fail at runtime - but give you the option of having checking in the cases where you want it.
Also, how do you then access nested objects, like data['key'][0]['attr'] in Python?