Cannot create a free standing bezier curve

In `Sketch.bezier`, the previous `_endPoint` has to exist before a bezier can be generated:
```python
def bezier(
self: T,
pts: Iterable[Point],
tag: Optional[str] = None,
forConstruction: bool = False,
) -> T:
"""
Construct an bezier curve.

The edge will pass through the last points, and the inner points
are bezier control points.
"""
p1 = self._endPoint()
val = Edge.makeBezier([Vector(*p) for p in pts])

return self.edge(val, tag, forConstruction)
```
Is there any particular reason for this? With this I can't create a loop consisting entirely of bezier curves, for example