def METHOD_NAME(self):
    # Add two traces
    self.figure.add_traces(
        [
            go.Sankey(arrangement="snap"),
            go.Histogram2dContour(line={"color": "cyan"}),
        ]
    )
    # Check access properties
    self.assertEqual(self.figure.data[-2].type, "sankey")
    self.assertEqual(self.figure.data[-2].arrangement, "snap")
    self.assertEqual(self.figure.data[-1].type, "histogram2dcontour")
    self.assertEqual(self.figure.data[-1].line.color, "cyan")
    # Check message
    new_uid1 = self.figure.data[-2].uid
    new_uid2 = self.figure.data[-1].uid
    self.figure._send_addTraces_msg.assert_called_once_with(
        [
            {"type": "sankey", "arrangement": "snap"},
            {"type": "histogram2dcontour", "line": {"color": "cyan"}},
        ]
    )