Use new style type annotations throughout the code
In many places the code uses old-style type annotations, i.e., as comments. This should be updated to the new Python 3 type annotations in code. E.g.:
x = 1 # type: int
should become x: int = 1
In many places the code uses old-style type annotations, i.e., as comments. This should be updated to the new Python 3 type annotations in code. E.g.:
x = 1 # type: int
should become x: int = 1