From a3e2f13bb7a4cfef6824fab97be5a7df9b86eff2 Mon Sep 17 00:00:00 2001
From: Dave Grijalva <grijalva@gmail.com>
Date: Tue, 13 Jan 2015 21:33:50 -0800
Subject: [PATCH] added documentation for HMAC Sign method

---
 hmac.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/hmac.go b/hmac.go
index 2d7f1bf..402ff08 100644
--- a/hmac.go
+++ b/hmac.go
@@ -66,6 +66,8 @@ func (m *SigningMethodHMAC) Verify(signingString, signature string, key interfac
 	return ErrInvalidKey
 }
 
+// Implements the Sign method from SigningMethod for this signing method.
+// Key must be []byte
 func (m *SigningMethodHMAC) Sign(signingString string, key interface{}) (string, error) {
 	if keyBytes, ok := key.([]byte); ok {
 		if !m.Hash.Available() {