docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self, 'available') and self.available is not None:
              _dict['available'] = self.available
          if hasattr(self, 'processing') and self.processing is not None:
              _dict['processing'] = self.processing
          if hasattr(self, 'failed') and self.failed is not None:
              _dict['failed'] = self.failed
          if hasattr(self, 'pending') and self.pending is not None:
              _dict['pending'] = self.pending
          return _dict