code: def test_viewer_load_schema(self):
      viewer = PerspectiveViewer()
      viewer.load({"a": str, "b": int, "c": bool, "d": str})
      for col in viewer.columns:
          assert col in ["a", "b", "c", "d"]
  
imports: import numpy
  import pandas
  from perspective import PerspectiveViewer, Table
label_desc: Use image node_id 6 for calling the TestViewer obj's underlying member method code with example usage: obj.test_viewer_load_schema() without return types