code: function deleteCustomLabel (label_id) {
    return new Promise (async (resolve, reject) => {
      if (!label_id) {
        reject('label_id required');
        return;
      }
      let options = {
        'method': 'DELETE',
        'path': '/' + label_id
      };
  
      try {
        let response = await  this.callCustomLabelsApi(options);
        resolve(response);
      } catch (e) {
        reject(e);
      }
    });
  }
docs: Deletes a custom label.
  @param  {Integer}  label_id  The ID of the custom label to delete.
  @return {Promise<Object>}  The API response
  @memberof  Client#
  @example
  Client.deleteCustomLabel(094730967209673)
  .then(res => {
  console.log(res); // {"success": true}
  });