message: Fixed single extraction dimension error
diff: @@ -973,7 +973,13 @@ class DruidDatasource(Model, BaseDatasource):
  if len(groupby) == 0 and not having_filters:
  del qry['dimensions']
  client.timeseries(**qry)
  - if not having_filters and len(groupby) == 1 and order_desc:
  +
  + if (
  + not having_filters and
  + len(groupby) == 1 and
  + order_desc and
  + not isinstance(list(qry.get('dimensions'))[0], dict)
  + ):
  dim = list(qry.get('dimensions'))[0]
  if timeseries_limit_metric:
  order_by = timeseries_limit_metric
  @@ -995,7 +1001,7 @@ class DruidDatasource(Model, BaseDatasource):
  if phase == 1:
  return query_str
  query_str += (
  - "//\nPhase 2 (built based on phase one's results)\n")
  + "// Phase 2 (built based on phase one's results)\n")
  df = client.export_pandas()
  qry['filter'] = self._add_filter_from_pre_query_data(
  df,
  @@ -1037,7 +1043,7 @@ class DruidDatasource(Model, BaseDatasource):
  if phase == 1:
  return query_str
  query_str += (
  - "//\nPhase 2 (built based on phase one's results)\n")
  + "// Phase 2 (built based on phase one's results)\n")
  df = client.export_pandas()
  qry['filter'] = self._add_filter_from_pre_query_data(
  df,
  