anchor.diff:  
   + Parameters
       + locatedAt: `-16.78,32.69` (string, required) - longitude, latitude; can occur multiple times for multiple locations
  -    + fields: `dewPointTemperatureInCelsius,maxAirTemperatureInFahrenheit,relativeGlobalRadiationInPercent,evaporationMakkinkInMillimeter,visibilityProbabilityLessThan200MeterInPercent,weatherCode,locatedAt,saturationDeficitInHectoPascal,precipitationProbabilityMoreThan4_4MillimeterInPercent` (string, required) - comma separated list of parameters to be contained inside response 
  +    + fields: `dewPointTemperatureInCelsius,feelsLikeTemperatureInCelsius,maxAirTemperatureInFahrenheit,relativeGlobalRadiationInPercent,evaporationMakkinkInMillimeter,visibilityProbabilityLessThan200MeterInPercent,weatherCode,locatedAt,saturationDeficitInHectoPascal,precipitationProbabilityMoreThan4_4MillimeterInPercent` (string, required) - comma separated list of parameters to be contained inside response
       + validFrom: `2016-12-13T11:00:00Z` (string, optional) - ISO8601 timestamp notation, means incl. this timestamp; always provide a time offset, e.g. 'Z' for UTC; optional: a request may provide correct offset (so that server can convert to UTC).
       + validUntil: `2016-12-13T12:00:00Z` (string, optional) - ISO8601 timestamp notation, means incl. this timestamp; always provide a time offset, e.g. 'Z' for UTC; optional: a request may provide correct offset (so that server can convert to UTC).
       + validPeriod: `PT0S,PT1H,PT3H,PT6H,PT12H,PT24H` (string, required) - comma separated list of periods to be retrieved. PT1H refers to one hour forecast periods.
  
positive.code:       },
        {  
           "dewPointTemperatureInCelsius":13.6,
           "visibilityProbabilityLessThan200MeterInPercent":0,
           "weatherCode":4,
           "locatedAt":[-16.78,32.69],
  
negative.code: 
  Here are relationship between observation periods and fields appropriately:
  
  - **PT0S** - airTemperatureInCelsius,airTemperatureInFahrenheit,airTemperatureInKelvin,dewPointTemperatureInCelsius,dewPointTemperatureInFahrenheit,dewPointTemperatureInKelvin,feelsLikeTemperatureInCelsius,feelsLikeTemperatureInFahrenheit,feelsLikeTemperatureInKelvin,airPressureAtSeaLevelInHectoPascal,windSpeedInMeterPerSecond,windSpeedInKnots,windSpeedInMilesPerHour,windSpeedInBeaufort,windSpeedInKilometerPerHour,windDirectionInDegree,effectiveCloudCoverInOcta,totalCloudCoverInOcta,cloudCoverLowerThan2000MeterInOcta,cloudCoverLowerThan5000MeterInOcta,globalRadiationInJoulePerSquareCentimeter,relativeHumidityInPercent,visibilityInMeter,weatherCode,clearSkyUVIndex,airTemperatureErrorInKelvin,windSpeedErrorInKnots,freezingLevelHeightInMeter,freezingRainProbabilityInPercent,noSnowPossibleBelowHeightInMeter,snowCertainAboveHeightInMeter,saturationDeficitInHectoPascal,visibilityProbabilityLessThan200MeterInPercent,visibilityProbabilityLessThan1000MeterInPercent
  - **PT1H** - windGustInMeterPerSecond,windGustInKnots,windGustInMilesPerHour,sunshineDurationInMinutes,precipitationAmountInMillimeter,precipitationAmountInInch,precipitationProbabilityInPercent,convectivePrecipitationProbabilityInPercent,maxPrecipitationAmountInMillimeter,precipitationType,hailProbabilityInPercent,directRadiationInJoulePerSquareCentimeter,globalRadiationInJoulePerSquareCentimeter,relativeGlobalRadiationInPercent,freshSnowfallInCentimeter,maxFreshSnowfallInCentimeter,relativeSunshineDurationInPercent,windGustProbabilityGreaterThan40KnotsInPercent
  - **PT3H** - maxWindSpeedInMeterPerSecond,maxWindSpeedInKnots,maxWindSpeedInMilesPerHour,maxWindGustInMeterPerSecond,maxWindGustInKnots,maxWindGustInMilesPerHour,minAirTemperatureInCelsius,minAirTemperatureInFahrenheit,minAirTemperatureInKelvin,maxAirTemperatureInCelsius,maxAirTemperatureInFahrenheit,maxAirTemperatureInKelvin,mostLikelyLowAirTemperatureInCelsius,mostLikelyLowAirTemperatureInFahrenheit,mostLikelyLowAirTemperatureInKelvin,mostLikelyHighAirTemperatureInCelsius,mostLikelyHighAirTemperatureInFahrenheit,mostLikelyHighAirTemperatureInKelvin,weatherCode
  - **PT6H** - maxWindSpeedInMeterPerSecond,maxWindSpeedInKnots,maxWindSpeedInMilesPerHour,maxWindGustInMeterPerSecond,maxWindGustInKnots,maxWindGustInMilesPerHour,minAirTemperatureInCelsius,minAirTemperatureInFahrenheit,minAirTemperatureInKelvin,maxAirTemperatureInCelsius,maxAirTemperatureInFahrenheit,maxAirTemperatureInKelvin,mostLikelyLowAirTemperatureInCelsius,mostLikelyLowAirTemperatureInFahrenheit,mostLikelyLowAirTemperatureInKelvin,mostLikelyHighAirTemperatureInCelsius,mostLikelyHighAirTemperatureInFahrenheit,mostLikelyHighAirTemperatureInKelvin,weatherCode,maxPrecipitationAmountInMillimeter,minPrecipitationAmountInMillimeter,precipitationProbabilityMoreThan0_2MillimeterInPercent,precipitationProbabilityMoreThan4_4MillimeterInPercent,precipitationDurationInMinutes,precipitationType,freshSnowfallInCentimeter,maxFreshSnowfallInCentimeter,effectiveCloudCoverInOcta
  