Look at flake8 B906

[enzbang]

Flake8 flags some code with the B906 check:

B906: visit_ function with no further call to a visit function. This is often an error, and will stop the visitor from recursing into the subnodes of a visited node. Consider adding a call self.generic_visit(node) at the end of the function. Will only trigger on function names where the part after visit_ is a valid ast type with a non-empty _fields attribute. This is meant to be enabled by developers writing visitors using the ast module, such as flake8 plugin writers.

See

src/e3/sys.py:122:5: B906 `visit_` function with no further calls to a visit function, which might prevent the `ast` visitor from properly visiting all nodes. Consider adding a call to `self.generic_visit(node)`.
and
src/e3/sys.py:127:5: B906 `visit_` function with no further calls to a visit function, which might prevent the `ast` visitor from properly visiting all nodes. Consider adding a call to `self.generic_visit(node)`.

We need to review that warning to see whether that's a false positive or a real bug in e3.sys