code: def test_set_stroke_opacity(self):
      symbol = Symbol(self.location, stroke_opacity=0.2)
      assert symbol.get_state()["stroke_opacity"] == 0.2
      symbol.stroke_opacity = 0.8
      assert symbol.get_state()["stroke_opacity"] == 0.8
  
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 5 for calling the SymbolTest obj's underlying member method code with example usage: obj.test_set_stroke_opacity() without return types