src/Type/Definition/InterfaceType.php
public static function assertInterfaceType($type)
    {
        Utils::invariant(
            $type instanceof self,
            'Expected ' . Utils::printSafe($type) . ' to be a GraphQL Interface type.'
        );

        return $type;
    }
public static function assertInterfaceType($type)
    {
        Utils::invariant(
            $type instanceof self,
            'Expected ' . Utils::printSafe($type) . ' to be a GraphQL Interface type.'
        );

        return $type;
    }
@param mixed $type

@return self