Vendor/phpspreadsheet/phpoffice/phpspreadsheet/src/PhpSpreadsheet/Calculation/Calculation.php
public function getImplementedFunctionNames()
    {
        $returnValue = [];
        foreach (self::$phpSpreadsheetFunctions as $functionName => $function) {
            if ($this->isImplemented($functionName)) {
                $returnValue[] = $functionName;
            }
        }

        return $returnValue;
    }
public function getImplementedFunctionNames()
    {
        $returnValue = [];
        foreach (self::$phpSpreadsheetFunctions as $functionName => $function) {
            if ($this->isImplemented($functionName)) {
                $returnValue[] = $functionName;
            }
        }

        return $returnValue;
    }
Get a list of implemented Excel function names.

@return array