code: def test_opacity_list(self):
      options = self._add_default_options(
          fill_opacity=[0.2, 0.4], stroke_opacity=[0.6, 0.7]
      )
      symbols = symbol_layer(self.locations, **options)
      fill_opacity_options = [
          symbol.fill_opacity for symbol in symbols.markers
      ]
      stroke_opacity_options = [
          symbol.stroke_opacity for symbol in symbols.markers
      ]
      assert fill_opacity_options == [0.2, 0.4]
      assert stroke_opacity_options == [0.6, 0.7]
  
imports: import unittest
  import pytest
  import numpy
  import traitlets
  from ..marker import MarkerOptions, Marker, Markers, Symbol, marker_layer, symbol_layer
label_desc: Use image node_id 16 for calling the SymbolLayer obj's underlying member method code with example usage: obj.test_opacity_list() without return types