protected function collectReferencedFormulaNames(AbstractQueryRequest $request) {
        $usedFormulaNames = NULL;

        // checking dimensions
        if (isset($request->dimensions)) {
            foreach ($request->dimensions as $dimension) {
                $dimensionName = $dimension->name;
                if ($request->findFormula($dimensionName) != NULL) {
                    ArrayHelper::addUniqueValue($usedFormulaNames, $dimensionName);
                }
            }
        }
        // checking measures
        if (isset($request->measures)) {
            foreach ($request->measures as $measure) {
                $measureName = $measure->name;
                if ($request->findFormula($measureName) != NULL) {
                    ArrayHelper::addUniqueValue($usedFormulaNames, $measureName);
                }
            }
        }
        // checking conditions
        if (isset($request->queries)) {
            foreach ($request->queries as $query) {
                $name = $query->name;
                if ($request->findFormula($name) != NULL) {
                    ArrayHelper::addUniqueValue($usedFormulaNames, $name);
                }
            }
        }

        return $usedFormulaNames;
    }
    protected function collectReferencedFormulaNames(AbstractQueryRequest $request) {
        $usedFormulaNames = NULL;

        // checking conditions
        if (isset($request->queries)) {
            foreach ($request->queries as $index => $query) {
                foreach ($query as $columnName => $values) {
                    if ($request->findFormula($columnName) != NULL) {
                        ArrayHelper::addUniqueValue($usedFormulaNames, $columnName);
                    }
                }
            }
        }
        // checking columns
        if ($request instanceof DatasetQueryRequest) {
            if (isset($request->columns)) {
                foreach ($request->columns as $columnName) {
                    if ($request->findFormula($columnName) != NULL) {
                        ArrayHelper::addUniqueValue($usedFormulaNames, $columnName);
                    }
                }
            }
        }

        return $usedFormulaNames;
    }