docs: function(jid_or_user_id) {
          var chatType;
          if (typeof jid_or_user_id === 'string') {
              chatType = jid_or_user_id.indexOf("muc") > -1 ? 'groupchat' : 'chat';
          } else if (typeof jid_or_user_id === 'number') {
              chatType = 'chat';
          } else {
              throw new Error(unsupportedError);
          }
          return chatType;
      }