build method Null safety

Implementation

@override
Widget build(BuildContext context) {
  // If [expanded] = true, render all panel elements (including summary), otherwise just renders panel summary.
  if (panel.expanded ?? false) {
    return KnowledgePanelExpandedCard(
      panel: panel,
      allPanels: allPanels,
    );
  }
  return InkWell(
    child: KnowledgePanelSummaryCard(panel),
    onTap: () {
      AnalyticsHelper.trackKnowledgePanelOpen(
        knowledgePanelName: panel.titleElement.toString(),
      );
      Navigator.push<Widget>(
        context,
        MaterialPageRoute<Widget>(
          builder: (BuildContext context) => KnowledgePanelPage(
            panel: panel,
            allPanels: allPanels,
          ),
        ),
      );
    },
  );
}