I made a typo in my code and replaced an = with a :, which resulted in a line of code that looked like: data = {} data["teapot"]: "turtle" To my surprise, this did not produce a syntax error, but I don't understand what it's doing. I then dumped the abstract syntax tree and it appears that it is some sort of type hint, although not one I've been able to find an example of elsewhere: >>> import ast >>> print(ast.dump(ast.parse("data['x']: 'turtle'"), indent=2)) Module( body=[ AnnAssign( target=Subscript( value=Name(id='data', ctx=Load()), slice=Constant(value='x'), ctx=Store()), annotation=Constant(value='turtle'), simple=0)], type_ignores=[]) What does this code mean? If it is, as I guess based on the AST, a type hint, does it have any practical use? Continue reading...
