code: def test_opacity_default(self):
      options = self._add_default_options()
      symbols = symbol_layer(self.locations, **options)
      for symbol in symbols.markers:
          assert symbol.fill_opacity == 1.0
          assert symbol.stroke_opacity == 1.0
  
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 14 for calling the SymbolLayer obj's underlying member method code with example usage: obj.test_opacity_default() without return types