Devise\Users\Permissions\RuleManager::ruleNameAvailable PHP Method

Checks rules array to see if rule/function name has already been used for rule

private ruleNameAvailable ( string $rule ) : boolean
$rule	string	Name of the rule being checked
return	boolean

    private function ruleNameAvailable($rule)
    {
        return in_array($rule, $this->RuleList->rules) ? false : true;
    }

RuleManager