code: def horizon_main_nav(context):
      
      if 'request' not in context:
          return {}
      current_dashboard = context['request'].horizon.get('dashboard', None)
      dashboards = []
      for dash in Horizon.get_dashboards():
          if dash.can_access(context):
              if callable(dash.nav) and dash.nav(context):
                  dashboards.append(dash)
              elif dash.nav:
                  dashboards.append(dash)
      return {'components': dashboards,
              'user': context['request'].user,
              'current': current_dashboard,
              'request': context['request']}
docs: Generates top-level dashboard navigation entries.