code: public function setDataType($dataType)
      {
          if (!in_array($dataType, self::$dataTypeValues)) {
              throw new Exception('Invalid datatype for chart data series values');
          }
          $this->dataType = $dataType;
  
          return $this;
      }
docs: Set Series Data Type.
  
  @param string $dataType Datatype of this data series
  Typical values are:
  DataSeriesValues::DATASERIES_TYPE_STRING
  Normally used for axis point values
  DataSeriesValues::DATASERIES_TYPE_NUMBER
  Normally used for chart data values
  
  @throws Exception
  
  @return DataSeriesValues