code: function (identifier)  {
      var path;
      if (identifier) {
        path = this.constructPath(constants.CHANNELS, identifier);
        return this.Core.DELETE(path);
      } else {
        return this.rejectRequest('Bad Request: A channel identifier is required.');
      }
    }
docs: Delete a channel
  @param  {String|Integer} identifier A Robin channel identifier
  @return {Function}                  A Promise