Test for dyadic rationals reports error about twenty-first HOT 1 CLOSED

DyadicRational { mantissa: 12516635689082565772, exponent: 4 } + DyadicRational { mantissa: 1171144540130836136, exponent: 3 } = DyadicRational { mantissa: 3714731192336059511, exponent: 2 }
thread 'amount::dyadic_rationals::dyadic_rationals_tests::add_sub_pbt' panicked at twenty-first/src/amount/dyadic_rationals.rs:155:9:
Right-hand-side argument cannot be larger than left-hand-side for subtraction.
LHS was: DyadicRational { mantissa: 3714731192336059511, exponent: 2 },
RHS: DyadicRational { mantissa: 12516635689082565772, exponent: 4 }