Broken `from_dict` in `RearrangeAssumptionStrategy`

[jaypantone]

The assert in this function is raised because d still contains workable: True. I'm not sure where that is supposed to be sent.

    @classmethod
    def from_dict(cls, d: dict) -> "RearrangeAssumptionStrategy":
        assumption = TrackingAssumption.from_dict(d.pop("assumption"))
        sub_assumption = TrackingAssumption.from_dict(d.pop("sub_assumption"))
        assert not d
        return cls(assumption, sub_assumption)