src/PeskyCMF/Scaffold/Form/ManyToManyRelationRecordsFormInput.php
public function setOptionLabelColumnForDefaultOptionsLoader($columnNameOrClosure) {
        if (
            !is_string($columnNameOrClosure)
            && !($columnNameOrClosure instanceof DbExpr)
            && !($columnNameOrClosure instanceof \Closure)
        ) {
            throw new \InvalidArgumentException(
                '$columnNameOrClosure argument must be a string, DbExpr or a Closure'
            );
        }
        $this->optionLabelColumnForDefaultOptionsLoader = $columnNameOrClosure;
        return $this;
    }
public function setOptionLabelColumnForDefaultOptionsLoader($columnNameOrClosure) {
        if (
            !is_string($columnNameOrClosure)
            && !($columnNameOrClosure instanceof DbExpr)
            && !($columnNameOrClosure instanceof \Closure)
        ) {
            throw new \InvalidArgumentException(
                '$columnNameOrClosure argument must be a string, DbExpr or a Closure'
            );
        }
        $this->optionLabelColumnForDefaultOptionsLoader = $columnNameOrClosure;
        return $this;
    }
Set source for options labels
@param string|\Closure $columnNameOrClosure
- string: column name
- \Closure: function (RecordInterface $record) { return 'value' }
@return $this
@throws \InvalidArgumentException