code: def test_marker_valid_location():
      m = Map()
      marker = Marker()
      marker.add_to(m)
      with pytest.raises(ValueError):
          m.render()
  
imports: import warnings
  import numpy
  import pytest
  from folium import GeoJson, Map, TileLayer
  from folium.map import CustomPane, Icon, LayerControl, Marker, Popup
  from folium.utilities import normalize
label_desc: Use image node_id 14 for calling a global function with example usage: test_marker_valid_location() without return types