function buildFeatureRain(name, externalId, featureName, unit) {
  return {
    name,
    external_id: `${externalId}:${featureName}`,
    selector: `${externalId}:${featureName}`,
    category: DEVICE_FEATURE_CATEGORIES.PRECIPITATION_SENSOR,
    type: DEVICE_FEATURE_TYPES.SENSOR.DECIMAL,
    unit,
    read_only: true,
    keep_history: true,
    has_feedback: false,
    min: 0,
    max: 100,
  };
}
@description Transforms Netatmo feature as Gladys feature.Precipitation per hour and sum of the day.
@param { string } name - Name device from Netatmo.
@param { string } externalId - Gladys external ID.
@param { string } featureName - Gladys feature constructor.
@param { string } unit - Gladys unit.
@returns { object } Gladys feature or undefined.
@example
buildFeatureRain(device_name, 'netatmo:device_id', 'rain', 'mm');