_fetchDataFromValues ({ dataFrom, specOptions }) {
    return Promise.all(dataFrom.map(async key => {
      const value = await this._get({ key, specOptions, keyOptions: {} })

      try {
        return JSON.parse(value)
      } catch (err) {
        this._logger.warn(`Failed to JSON.parse value for '${key}',` +
          ' please verify that your secret value is correctly formatted as JSON.')
      }
    }))
  }
Fetch Kubernetes secret property values.
@param {string[]} dataFrom - Array of secret keys in the backend
@param {string} specOptions - Options set on spec level that might be interesting for the backend
@returns {Promise} Promise object representing secret property values.