code: public static AssignmentGuardFinder newInstance(final String candidateName,
              final ControlFlowBlock controlFlowBlock) {
          checkArgument(!candidateName.isEmpty());
          return new AssignmentGuardFinder(candidateName, checkNotNull(controlFlowBlock));
      }
docs: Creates a new instance of this class. None of the arguments must be
  {@code null}.
  
  @param candidateName
  name of the lazy variable. Must not be empty!
  @param controlFlowBlock
  the control flow block which is supposed to contain an
  {@link AssignmentGuard}.
  @return a new instance of this class.