new_contents: default_style = {
      'alpha': .6,
      'width': 1,
      'node_size': 100,
      'node_color': '#2EB1E6',
      'edge_color': '#cccccc',
  }
  
  solution_style = default_style.copy()
  solution_style.update(node_color='#ff0000')
  
subject: Add graphics definition for easier standardized graph printing.