Add missing import of Pose3

[varunagrawal]

Fixes bug accidentally introduced by #844.

[johnwlambert]

Thanks for catching the missing import.

I am using python black https://github.com/psf/black. I find it to be the cleanest of all the Python auto-formatters. Could you take a look at it? If we could switch to it, I would be quite happy : - )

Python black is used by 73K repos. Yapf is used by just 22K repos, according to Github

[varunagrawal]

Yeah Github stars and users don't mean much since we follow the Google Style for Python (which recommends yapf).

[varunagrawal]

I also like black because it is very opinionated. Unfortunately, formatting all the python code is a chore I don't want to undertake any time soon.

[ProfFan]

What is the biggest advantage of black over yapf?

[johnwlambert]

What is the biggest advantage of black over yapf?

I think the function signatures are much easier to read with Black. For one example, YAPF formats this as:

def ellipsoid(rx: float, ry: float, rz: float,
              n: int) -> Tuple[np.ndarray, np.ndarray, np.ndarray]:

but Black formats it as:

def ellipsoid(
    rx: float, ry: float, rz: float, n: int
) -> Tuple[np.ndarray, np.ndarray, np.ndarray]:

I find the latter a lot easier to read and review.

Black is also quite fast: https://news.ycombinator.com/item?id=17155048