How to use the vscode-languageserver-protocol.DiagnosticSeverity.Warning function in vscode-languageserver-protocol

public setDiagnosticInfo(bufnr: number, diagnostics: ReadonlyArray): void {
    let lnums = [0, 0, 0, 0]
    let info = { error: 0, warning: 0, information: 0, hint: 0, lnums }
    for (let diagnostic of diagnostics) {
      switch (diagnostic.severity) {
        case DiagnosticSeverity.Warning:
          info.warning = info.warning + 1
          lnums[1] = lnums[1] || diagnostic.range.start.line + 1
          break
        case DiagnosticSeverity.Information:
          info.information = info.information + 1
          lnums[2] = lnums[2] || diagnostic.range.start.line + 1
          break
        case DiagnosticSeverity.Hint:
          info.hint = info.hint + 1
          lnums[3] = lnums[3] || diagnostic.range.start.line + 1
          break
        default:
          lnums[0] = lnums[0] || diagnostic.range.start.line + 1
          info.error = info.error + 1
      }
    }

this.client.onConfigDiagnosticsReceived(diag => {
      let { body } = diag
      if (body) {
        let { configFile, diagnostics } = body
        let uri = Uri.file(configFile)
        let language = this.findLanguage(uri)
        if (!language) return
        if (diagnostics.length == 0) {
          this.client.diagnosticsManager.configFileDiagnosticsReceived(uri.toString(), [])
        } else {
          let range = Range.create(Position.create(0, 0), Position.create(0, 1))
          let { text, code, category } = diagnostics[0]
          let severity = category == 'error' ? DiagnosticSeverity.Error : DiagnosticSeverity.Warning
          let diagnostic = Diagnostic.create(range, text, severity, code)
          this.client.diagnosticsManager.configFileDiagnosticsReceived(uri.toString(), [diagnostic])
        }
      }
    }, null, this.disposables)

private getDiagnosticSeverity(diagnostic: Proto.Diagnostic): DiagnosticSeverity {
    if (
      this.reportStyleCheckAsWarnings &&
      this.isStyleCheckDiagnostic(diagnostic.code) &&
      diagnostic.category === PConst.DiagnosticCategory.error
    ) {
      return DiagnosticSeverity.Warning
    }

    switch (diagnostic.category) {
      case PConst.DiagnosticCategory.error:
        return DiagnosticSeverity.Error

      case PConst.DiagnosticCategory.warning:
        return DiagnosticSeverity.Warning

      case PConst.DiagnosticCategory.suggestion:
        return DiagnosticSeverity.Information

      default:
        return DiagnosticSeverity.Error
    }
  }

private getDiagnosticSeverity(diagnostic: Proto.Diagnostic): DiagnosticSeverity {
    if (
      this.reportStyleCheckAsWarnings &&
      this.isStyleCheckDiagnostic(diagnostic.code) &&
      diagnostic.category === PConst.DiagnosticCategory.error
    ) {
      return DiagnosticSeverity.Warning
    }

    switch (diagnostic.category) {
      case PConst.DiagnosticCategory.error:
        return DiagnosticSeverity.Error

      case PConst.DiagnosticCategory.warning:
        return DiagnosticSeverity.Warning

      case PConst.DiagnosticCategory.suggestion:
        return DiagnosticSeverity.Information

      default:
        return DiagnosticSeverity.Error
    }
  }

diagnostics.forEach(diagnostic => {
      let { source, code, severity, message } = diagnostic
      let s = getSeverityName(severity)[0]
      let str = `[${source}${code ? ' ' + code : ''}] [${s}] ${message}`
      let filetype = 'Error'
      if (ft === '') {
        switch (diagnostic.severity) {
          case DiagnosticSeverity.Hint:
            filetype = 'Hint'
            break
          case DiagnosticSeverity.Warning:
            filetype = 'Warning'
            break
          case DiagnosticSeverity.Information:
            filetype = 'Info'
            break
        }
      } else {
        filetype = ft
      }
      docs.push({ filetype, content: str })
    })
    if (useFloat) {

private getDiagnosticSeverity(diagnostic: Proto.Diagnostic): DiagnosticSeverity {
    if (
      this.reportStyleCheckAsWarnings &&
      this.isStyleCheckDiagnostic(diagnostic.code) &&
      diagnostic.category === PConst.DiagnosticCategory.error
    ) {
      return DiagnosticSeverity.Warning
    }

    switch (diagnostic.category) {
      case PConst.DiagnosticCategory.error:
        return DiagnosticSeverity.Error

      case PConst.DiagnosticCategory.warning:
        return DiagnosticSeverity.Warning

      case PConst.DiagnosticCategory.suggestion:
        return DiagnosticSeverity.Information

      default:
        return DiagnosticSeverity.Error
    }
  }

private getDiagnosticSeverity(diagnostic: Proto.Diagnostic): DiagnosticSeverity {
    if (
      this.reportStyleCheckAsWarnings &&
      this.isStyleCheckDiagnostic(diagnostic.code) &&
      diagnostic.category === PConst.DiagnosticCategory.error
    ) {
      return DiagnosticSeverity.Warning
    }

    switch (diagnostic.category) {
      case PConst.DiagnosticCategory.error:
        return DiagnosticSeverity.Error

      case PConst.DiagnosticCategory.warning:
        return DiagnosticSeverity.Warning

      case PConst.DiagnosticCategory.suggestion:
        return DiagnosticSeverity.Information

      default:
        return DiagnosticSeverity.Error
    }
  }