See `cirq.protocols.SupportsApproximateEquality`.

def _approx_eq_(self, other: Any, atol: Union[int, float]) -> bool:
        """See `cirq.protocols.SupportsApproximateEquality`."""
        if not isinstance(other, type(self)):
            return NotImplemented
        return cirq.protocols.approx_eq(
            self._moments,
            other._moments,
            atol=atol
        ) and self._device == other._device