Keep imports alphabetically sorted and their order homogeneous across
Python source files.
The isort project has more feature and is more active than the
flake8-import-order plugin.
Most issues caught were simply import ordering from the same module.
Where imports were purposefully placed out of order, tag with
isort:skip.
Typically, the __args__ attribute of type annotations is a tuple
containing arguments for the types (ex. The __args__ of `List[int]` is
`(int,)`). But some kind of types has non tuple __args__ attribute.
For example, `nptyping.NDArray` is one of them.
This fixes the TypeError when the invalid __args__ attribute found.
