libboost-contract1.67.0 1.67.0-13ubuntu2 (amd64 binary) in ubuntu focal

 This package forms part of the Boost C++ Libraries collection.
 .
 All contract programming features are supported: Subcontracting,
 class invariants, postconditions (with old and return values),
 preconditions, customizable actions on assertion failure (e.g.,
 terminate or throw), optional compilation and checking of assertions,
 etc.