How to use the @swim/util.Severity.ERROR_LEVEL function in @swim/util

protected onLintFailure(failure: tslint.RuleFailure): void {
    let tag: Tag;
    if (failure.getEndPosition().getPosition() - failure.getStartPosition().getPosition() > 1) {
      const start = Target.tslinkMark(failure.getStartPosition());
      const end = Target.tslinkMark(failure.getEndPosition(), -1, failure.getFailure());
      tag = Span.from(start, end);
    } else {
      tag =  Target.tslinkMark(failure.getStartPosition(), 0, failure.getFailure());
    }
    const severity = Target.tslintSeverity(failure.getRuleSeverity());
    if (severity.level() >= Severity.ERROR_LEVEL) {
      this.failed = true;
    }

    const sourceFile = (failure as any).sourceFile;
    const input = Unicode.stringInput(sourceFile.text).id(sourceFile.fileName);
    const diagnostic = new Diagnostic(input, tag, severity, failure.getRuleName(), null, null);
    console.log(diagnostic.toString(OutputSettings.styled()));
  }

protected onCompileError(error: ts.Diagnostic): void {
    let message = error.messageText;
    if (typeof message !== "string") {
      message = message.messageText;
    }
    const severity = Target.tsSeverity(error.category);
    if (severity.level() >= Severity.ERROR_LEVEL) {
      this.failed = true;
    }
    if (error.file) {
      let tag: Tag;
      if (error.length! > 1) {
        const start = Target.tsMark(error.start!, error.file);
        const end = Target.tsMark(error.start! + error.length! - 1, error.file, message);
        tag = Span.from(start, end);
      } else {
        tag = Target.tsMark(error.start!, error.file, message);
      }

      const input = Unicode.stringInput(error.file.text).id(error.file.fileName);
      const diagnostic = new Diagnostic(input, tag, severity, "" + error.code, null, null);
      console.log(diagnostic.toString(OutputSettings.styled()));
    } else {