code: def test_set_mapbox_token():
      with ExitStack() as stack:
          stack.enter_context(
              mock.patch("dtale.charts.utils.MAPBOX_TOKEN", None)
          )
  
          chart_utils.set_mapbox_token("test")
          assert chart_utils.MAPBOX_TOKEN == "test"
  
file_path: dtale/tests/dtale/charts/test_utils.py
imports: import mock
  import pytest
  import dtale.charts.utils
  from tests import ExitStack
  from tests.dtale.test_charts import build_col_def
label_desc: Use image node_id 1 for calling a global function with example usage: test_set_mapbox_token() without return types