https://www.boost.org/doc/libs/1_78_0/libs/contract/doc/html/boost/contract/specify_precondit_idm35978.html
Class template specify_precondition_old_postcondition_except
class templatespecifypreconditionoldpostcondition
https://www.boost.org/doc/libs/1_78_0/libs/contract/doc/html/boost/contract/specify_postcondi_idm35905.html
Class template specify_postcondition_except
class templatespecifypostconditionexcept
https://www.boost.org/doc/libs/1_78_0/libs/contract/doc/html/boost/contract/postcondition_failure.html
Function postcondition_failure
functionpostconditionfailure