code: def has_option_tag(self, section, option, tag):
          
          return self.has_option_tags(section, option, [tag])
docs: Convenience function accessing has_option_tags() for a single tag: see
          documentation for that function.
          NB calling has_option_tags() directly is preferred for simplicity.
  
          Parameters
          -----------
          self : ConfigParser object
              The ConfigParser object (automatically passed when this is appended
              to the ConfigParser class)
          section : string
              The section of the ConfigParser object to read
          option : string
              The ConfigParser option to look for
          tag : string
              The name of the subsection to look in, if not found in [section]
  
          Returns
          --------
          Boolean
              Is the option in the section or [section-tag]