code: def import_fonts(style_less, fontname, font_subdir):
      
  
      ftype_dict = {'woff2': 'woff2',
                    'woff': 'woff',
                    'ttf': 'truetype',
                    'otf': 'opentype',
                    'svg': 'svg'}
  
      define_font = (
          "@font-face {{font-family: {fontname};\n\tfont-weight:"
          "{weight};\n\tfont-style: {style};\n\tsrc: local('{fontname}'),"
          "\n\turl('fonts{sepp}{fontfile}') format('{ftype}');}}\n")
      fontname = fontname.split(',')[0]
      fontpath = os.path.join(fonts_dir, font_subdir)
      for fontfile in os.listdir(fontpath):
          if '.txt' in fontfile or 'DS_' in fontfile:
              continue
          weight = 'normal'
          style = 'normal'
          if 'medium' in fontfile:
              weight = 'medium'
          elif 'ital' in fontfile:
              style = 'italic'
          ft = ftype_dict[fontfile.split('.')[-1]]
          style_less += define_font.format(
              fontname=fontname,
              weight=weight,
              style=style,
              sepp='/',
              fontfile=fontfile,
              ftype=ft)
          send_fonts_to_jupyter(os.path.join(fontpath, fontfile))
  
      return style_less
docs: Copy all custom fonts to ~/.jupyter/custom/fonts/ and
      write import statements to style_less