I'm opening this issue as I don't want to work on it for the moment.

I have noticed many errors when I tried to implement rel_center :

• test_inflate_ip__larger does not check what it is supposed to check (duplicate code of test_inflate_ip__smaller)
• test_inflate_ip__smaller's docstring is incorrect
• each attributes are not checked with literal values if they have the right values. You might think calculating it based on other attributes garantie that the attributes return the right value but this shouldn't be the case ! Not for tests at least ! This is why I would like to see a test that checks if the attributes return the right value based on literal values.