code: public static function FIXEDFORMAT($value, $decimals = 2, $no_commas = false)
      {
          $value = Functions::flattenSingleValue($value);
          $decimals = Functions::flattenSingleValue($decimals);
          $no_commas = Functions::flattenSingleValue($no_commas);
  
          // Validate parameters
          if (!is_numeric($value) || !is_numeric($decimals)) {
              return Functions::NAN();
          }
          $decimals = floor($decimals);
  
          $valueResult = round($value, $decimals);
          if ($decimals < 0) {
              $decimals = 0;
          }
          if (!$no_commas) {
              $valueResult = number_format($valueResult, $decimals);
          }
  
          return (string) $valueResult;
      }
docs: FIXEDFORMAT.
  
  @param mixed $value Value to check
  @param int $decimals
  @param bool $no_commas
  
  @return string