protected function buildRulesArray()
    {
        if (method_exists($this, $this->context)) {
            $rules = $this->{$this->context}();
        } elseif (isset($this->rules[$this->context])) {
            $rules = $this->rules[$this->context];
        } else {
            throw new InvalidArgumentException("Undefined validation context: " . $this->context);
        }
        return $this->bindPlaceholders($rules);
    }