docs: function getCustomLabelsByPsid (psid) {
    return new Promise (async (resolve, reject) => {
      if (!psid) {
        reject('PSID required');
      }
  
      let options = {
        'path': `/${psid}/custom_labels`
      };
  
      try {
        let response = await  this.callCustomLabelsApi(options);
        resolve(response);
      } catch (e) {
        reject(e);
      }
    });
  }