I think that thing X superceding thing Y is equivalent to thing Y subceding to thing X. In this case, if black becomes the standard for defining appropriate st

I think that thing X superceding thing Y is equivalent to thing Y subceding to thing X. In this case, if black becomes the standard for defining appropriate style then it is superceding pep8 as the standard for style (many styles consistent with pep8 are not black outputs, so if black's style becomes mandatory, it is a ruling against these previously accepted alternatives).