code: def test_aggregates_widget_load(self):
      aggs = {"a": Aggregate.AVG, "b": Aggregate.LAST}
      data = {"a": [1, 2, 3], "b": ["a", "b", "c"]}
      widget = PerspectiveWidget(data, aggregates=aggs)
      assert widget.aggregates == aggs
  
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 1 for calling the TestAggregates obj's underlying member method code with example usage: obj.test_aggregates_widget_load() without return types