docstr: add text string
  
  Args:
      text (str): text string written to pdf, with current
                  global indent level
      style (str): styles applied to the text
                  'B': bold,
                  'I': italic,
                  'U': underline,
                  or any combination of above
  Returns: HTML String
code: def __add_text(text: str, style=""):
      """
      add text string
  
      Args:
          text (str): text string written to pdf, with current
                      global indent level
          style (str): styles applied to the text
                      'B': bold,
                      'I': italic,
                      'U': underline,
                      or any combination of above
      Returns: HTML String
      """
      if "B" in style:
          text = "<b>%s</b>" % text
      if "I" in style:
          text = "<i>%s</i>" % text
      if "U" in style:
          text = "<u>%s</u>" % text
      return text
  
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 18 for calling the CustomHtml obj's underlying member method code with example usage: obj.__add_text(text, style) and returns: text