code: def test_aggregates_viewer_setattr(self):
      viewer = PerspectiveViewer()
      viewer.aggregates = {"a": Aggregate.AVG}
      assert viewer.aggregates == {"a": "avg"}
  
file_path: perspective/python/perspective/perspective/tests/core/test_aggregates.py
imports: from pytest import raises
  from perspective import PerspectiveError, PerspectiveViewer, PerspectiveWidget, Aggregate, Table
label_desc: Use image node_id 9 for calling the TestAggregates obj's underlying member method code with example usage: obj.test_aggregates_viewer_setattr() without return types