def MUST(m)
      RequirementLevel::High.new(m, false, subject, *challenges).result
    end
def MUST(m)
      RequirementLevel::High.new(m, false, subject, *challenges).result
    end
Create a new expection target

 @api private

 @param subject [Proc] The value which is compared with the expected value.
 rubocop:disable Style/MethodName
 rubocop:disable Naming/UncommunicativeMethodParamName
 @api public

 This word, or the terms "REQUIRED" or "SHALL", mean that the
 definition is an absolute requirement of the specification.

 @example _Absolute requirement_ definition
   it { 'foo'.upcase }.MUST eql 'FOO'

 @param m [#matches?] The matcher.

 @return [Result::Fail, Result::Pass] Report if the spec pass or fail.