code: def dump(self):
          
          return [
              {
                  'context_name': context.name,
                  'via': getattr(self._via_by_context.get(context),
                                 'name', None),
                  'refs': self._refs_by_context.get(context),
              }
              for context, key in sorted(self._key_by_context.items(),
                                         key=lambda c_k: c_k[0].context_id)
          ]
docs: For testing, return a list of dicts describing every currently
          connected context.