def hash_bytes(value, hasher=hashlib.sha256):<EOL>
return hmac.new(get_secret(), value, hasher).hexdigest()<EOL>
Generate a hash for a bytes value.

The hash will be generated by generating a hash with HMAC using the
session secret as the key and the given hash function.

:param value: Bytes value to hash
:param hasher: Hash function to use.
:return: Hexadecimal presentation of the hash as a string