code: public function setDoubleValue($value = null)
      {
          if ($value != null && !is_double($value)) {
              throw new \InvalidArgumentException('Expected an double value.');
          }
  
          $this->type = Cell::DOUBLE_TYPE;
          $this->value = $value;
  
          return $this;
      }
docs: @param double $value
  
  @return $this