CrudKit\Data\ArrayDataProvider::createItem PHP Method

    public function createItem(array $values)
    {
        foreach ($values as $formKey => $formValue) {
            if (!$this->isFieldInSchema($formKey)) {
                throw new \InvalidArgumentException("The Column [{$formKey}] is not defined.");
            }
        }
        $this->data[] = $values;
        end($this->data);
        return key($this->data);
    }