code: def _parse_options(opts, delim):
      
      options = _CaseInsensitiveDictionary()
      for uriopt in opts.split(delim):
          key, value = uriopt.split("=")
          if key.lower() == 'readpreferencetags':
              options.setdefault(key, []).append(value)
          else:
              if key in options:
                  warnings.warn("Duplicate URI option '%s'." % (key,))
              options[key] = unquote_plus(value)
  
      if 'tlsInsecure' in options:
          for implicit_option in _IMPLICIT_TLSINSECURE_OPTS:
              if implicit_option in options:
                  warn_msg = "URI option '%s' overrides value implied by '%s'."
                  warnings.warn(warn_msg % (options.cased_key(implicit_option),
                                            options.cased_key('tlsInsecure')))
                  continue
              options[implicit_option] = options['tlsInsecure']
  
      return options
docs: Helper method for split_options which creates the options dict.
      Also handles the creation of a list for the URI tag_sets/
      readpreferencetags portion and the use of the tlsInsecure option.