How to get string representation of hmac_md5?

Hello everybody,

I'm trying to get the string representation of the hmac_md5 function found in the workato SDK functions.

The way I'm using it is like so:

vendor_code = input['vendor_code']
secret_key = input['secret_key']

request_time = now.utc.strftime("%Y-%m-%d %H:%M:%S")

contactenated = vendor_code.length.to_s + vendor_code.to_s + request_time.length.to_s + request_time + request_time.to_s
hash_hmac = contactenated.hmac_md5(secret_key)
header = "code=\""+vendor_code+"\" date=\""+request_time+"\" hash=\""+hash_hmac + "\""

{x_avangate_authetication_header: hash_hmac }

But the value I'm getting back is 

{
header: X-Avangate-Authentication,
value: 0x8d1e4a67056622c900bcd913ef114927
},

I can only assume that it returns a hex value, but I have no way of checking that.

I also tried using the decode_hex function from the whitelisted SDK methods, but no luck on that either.

Normally I'd expect to get back something like this

code="250111206876" date="2020-07-15 13:45:02" hash="48c51eb6c55ceb7e313e6dfe5cb74178"

I'm not entirely sure how to proceed from here. Any pointing in the right direction is appreciated.