What

Fix a bug. Right now the only value that works is 0. You should never test with 0.

Why

Bugs are bad.

The durable storage contains bytes, in binary, not encoded as hexa.

The test has been updated.

Document the interface of any function added or modified (see the coding guidelines)
Document any change to the user interface, including configuration parameters (see node configuration)
Provide automatic testing (see the testing guide).
For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
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Select as Assignee the next person who should take action on that MR