private function getFieldArgNode($type, $fieldName, $argName)
    {
        $nodes = $this->getAllFieldArgNodes($type, $fieldName, $argName);

        return $nodes[0] ?? null;
    }
private function getFieldArgNode($type, $fieldName, $argName)
    {
        $nodes = $this->getAllFieldArgNodes($type, $fieldName, $argName);

        return $nodes[0] ?? null;
    }
private function getFieldArgNode ( $ type , $ fieldName , $ argName ) { $ nodes = $ this -> getAllFieldArgNodes ( $ type , $ fieldName , $ argName ) ; return $ nodes [ 0 ] ?? null ; }
@param ObjectType|InterfaceType $type
@param string                   $fieldName
@param string                   $argName

@return InputValueDefinitionNode|null
@param ObjectType|InterfaceType $type @param string $fieldName @param string $argName