code: def setUp(self):
      self.locations = [(-5.0, 5.0), (10.0, 10.0)]
      self.symbols = [
          Symbol(location=location) for location in self.locations
      ]
  
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 1 for calling the MarkersTest obj's underlying member method code with example usage: obj.setUp() without return types