Bug in `derive`

[nicolas-popsize]

Hi,
for some picture

src/garmentiq/landmark/derivation/derive_keypoint_coord.py
def derive_keypoint_coord(...) -> Optional[Tuple[float, float]] returns float

So src/garmentiq/landmark/derive.py
derived_coord = tuple(float(x) for x in process(**args)) returns error:

    metadata, outputs = tailor.measure(
  File "xxxxxxxxxxxxx/garmentiq/tailor.py", line 641, in measure
    derived_coords, updated_detection_dict = self.derive(
  File "xxxxxxxxxxxxx/garmentiq/tailor.py", line 312, in derive
    derived_coords, updated_detection_dict = landmark.derive(
  File "xxxxxxxxxxxxx/garmentiq/landmark/derive.py", line 41, in derive
    derived_coord = tuple(float(x) for x in process(**args))
TypeError: 'NoneType' object is not iterable

I think the code of should handle the case where return type of derive_keypoint_coord is None, as the return type is Optional[...]

[nicolas-popsize]

Solution is very simple:

        args = prepare_args(non_predefined_landmark[k], derivation_dict, **extra_args)
        derived_coord = process(**args)
        if derived_coord is None:
            continue
        derived_coord = tuple(float(x) for x in derived_coord)
        derived_coords[k] = derived_coord