code: public static function MODE(...$args)
      {
          $returnValue = Functions::NA();
  
          // Loop through arguments
          $aArgs = Functions::flattenArray($args);
  
          $mArgs = [];
          foreach ($aArgs as $arg) {
              // Is it a numeric value?
              if ((is_numeric($arg)) && (!is_string($arg))) {
                  $mArgs[] = $arg;
              }
          }
  
          if (!empty($mArgs)) {
              return self::modeCalc($mArgs);
          }
  
          return $returnValue;
      }
docs: MODE.
  
  Returns the most frequently occurring, or repetitive, value in an array or range of data
  
  Excel Function:
  MODE(value1[,value2[, ...]])
  
  @category Statistical Functions
  
  @param mixed ...$args Data values
  
  @return float