refactor(geometry): use "AttrsMixin" in "Box3D"

tensorbay/geometry/box.py

@@ -19,7 +19,7 @@
 import warnings
 from typing import Dict, Iterable, Optional, Tuple, Type, TypeVar
 
-from ..utility import MatrixType, ReprMixin, ReprType, UserSequence, common_loads
+from ..utility import AttrsMixin, MatrixType, ReprMixin, ReprType, UserSequence, attr, common_loads
 from .transform import Transform3D
 from .vector import Vector2D, Vector3D
 
@@ -324,7 +324,7 @@ def area(self) -> float:
         return self.width * self.height
 
 
-class Box3D(ReprMixin):
+class Box3D(AttrsMixin, ReprMixin):  # pylint: disable=too-many-ancestors
     """This class defines the concept of Box3D.
 
     :class:`Box3D` contains the information of a 3D bounding box such as the transform,
@@ -363,6 +363,9 @@ class Box3D(ReprMixin):
     _repr_type = ReprType.INSTANCE
     _repr_attrs: Tuple[str, ...] = ("size", "translation", "rotation")
 
+    _size: Vector3D = attr(key="size")
+    _transform: Transform3D = attr(key=None)
+
     def __init__(
         self,
         size: Iterable[float],
@@ -413,10 +416,6 @@ def _line_intersect(length1: float, length2: float, midpoint_distance: float) ->
         intersect_length = min(line1_max, line2_max) - max(line1_min, line2_min)
         return intersect_length if intersect_length > 0 else 0
 
-    def _loads(self, contents: Dict[str, Dict[str, float]]) -> None:
-        self._size = Vector3D.loads(contents["size"])
-        self._transform = Transform3D.loads(contents)
-
     @classmethod
     def loads(cls: Type[_B3], contents: Dict[str, Dict[str, float]]) -> _B3:
         """Load a :class:`Box3D` from a dict containing the coordinates of the 3D box.
@@ -567,6 +566,4 @@ def dumps(self) -> Dict[str, Dict[str, float]]:
             }
 
         """
-        contents = self._transform.dumps()
-        contents["size"] = self.size.dumps()
-        return contents
+        return self._dumps()