docstr: Returns css file path
code: def style(self):
      """Returns css file path"""
      return self._style
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import datetime
  from yattag import Doc, indent
label_desc: Use image node_id 3 for calling the CustomHtml obj's underlying member method code with example usage: obj.style() and returns: self