code: def test_calc_arrow_width():
      assert _calc_arrow_width(0.4, max_strength=0.5) == approx(
          3.3, abs=0.01
      )
      assert _calc_arrow_width(0.2, max_strength=0.5) == approx(
          1.7, abs=0.01
      )
      assert _calc_arrow_width(-0.2, max_strength=0.5) == approx(
          1.7, abs=0.01
      )
      assert _calc_arrow_width(0.5, max_strength=0.5) == approx(
          4.1, abs=0.01
      )
      assert _calc_arrow_width(0.35, max_strength=0.5) == approx(
          2.9, abs=0.01
      )
      assert _calc_arrow_width(100, max_strength=101) == approx(
          4.06, abs=0.01
      )
      assert _calc_arrow_width(100, max_strength=0) == 4.1
  
      with pytest.raises(ValueError):
          _calc_arrow_width(100, max_strength=-1)
  
file_path: dowhy/tests/utils/test_plotting.py
imports: import networkx
  import numpy
  import pandas
  import pytest
  from _pytest.python_api import approx
  from dowhy.utils import plot, plot_adjacency_matrix
  from dowhy.utils.networkx_plotting import plot_causal_graph_networkx
  from dowhy.utils.plotting import _calc_arrow_width, bar_plot
label_desc: Use image node_id 5 for calling a global function with example usage: test_calc_arrow_width() without return types