I was going through the Amazon Product Advertising API [REST signature docs](http://docs.aws.amazon.com/AWSECommerceService/latest/DG/rest-signature.html#rest_detailedexample) and I got stuck at #8 

> 
> Calculate an RFC 2104-compliant HMAC with the SHA256 hash algorithm using the string above with our "dummy" Secret Access Key: 1234567890. For more information about this step, see documentation and code samples for your programming language.
> 
> 
> 

Nevermind, managed to get it on one more try with the help of [Calculating a SHA hash with a string + secret key in python](https://stackoverflow.com/questions/1306550/calculating-a-sha-hash-with-a-string-secret-key-in-python). Will post answer below.