code: public static function COUNTA(...$args)
      {
          $returnValue = 0;
  
          // Loop through arguments
          $aArgs = Functions::flattenArray($args);
          foreach ($aArgs as $arg) {
              // Is it a numeric, boolean or string value?
              if ((is_numeric($arg)) || (is_bool($arg)) || ((is_string($arg) && ($arg != '')))) {
                  ++$returnValue;
              }
          }
  
          return $returnValue;
      }
docs: COUNTA.
  
  Counts the number of cells that are not empty within the list of arguments
  
  Excel Function:
  COUNTA(value1[,value2[, ...]])
  
  @category Statistical Functions
  
  @param mixed ...$args Data values
  
  @return int