code: def _add_trace(self, stream_vis):
      stream_vis.trace_index = len(self.widget.data)
      trace = self._create_trace(stream_vis)
      if stream_vis.opacity is not None:
          trace.opacity = stream_vis.opacity
      self.widget.add_trace(trace)
  
file_path: tensorwatch/tensorwatch/plotly/base_plotly_plot.py
imports: from ..vis_base import VisBase
  import time
  from abc import abstractmethod
  from ..None import utils
label_desc: Use image node_id 2 for calling the BasePlotlyPlot obj's underlying member method code with example usage: obj._add_trace(stream_vis) without return types