Signer is writable stream in crypto

node/node-0.11.d.ts

@@ -1089,7 +1089,7 @@ declare module "crypto" {
         setAutoPadding(auto_padding: boolean): void;
     }
     export function createSign(algorithm: string): Signer;
-    interface Signer {
+    interface Signer extends NodeJS.WritableStream {
         update(data: any): void;
         sign(private_key: string, output_format: string): string;
     }