Although the CPython implementation contains an LL(1) parser (which is being deprecated for a new PEG parser), the grammar contains bits that are not context-fr

Although the CPython implementation contains an LL(1) parser (which is being deprecated for a new PEG parser), the grammar contains bits that are not context-free, which involved a pre-parsing step before being fed into the LL(1) parser. That structure isn’t particularly good and it’d be beneficial for a new implementation to use something else.