code: def generate_html():
      
      html_file = open(html_filename, "w")
      html_file.write("<html><body>")
      html_file.write("<h1>Here are some graphs for you!</h1>")
      for image in [lines_filename, bars_filename, histogram_filename]:
          html_file.write("<div><h2>{0}</h2><img src='{0}' /></div>".format(image))
      html_file.write("</body></html>")
      html_file.close()
docs: Generate an HTML file incorporating the images produced by this script