Fix a number of flake8 errors

Broadly three things here:

* disable W504 which seems a bit whacko
* remove a bunch of `as e` expressions from exception handlers that don't use
  them
* use `r""` for strings which include backslashes

Also, we don't use pep8 any more, so we can get rid of the duplicate config
there.

1 files changed, 8 insertions, 9 deletions

diff --git a/setup.cfg b/setup.cfg
index 52feaa9cc7..b6b4aa740d 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -14,17 +14,16 @@ ignore =
     pylint.cfg
     tox.ini
 
-[pep8]
-max-line-length = 90
-#  W503 requires that binary operators be at the end, not start, of lines. Erik
-#  doesn't like it.  E203 is contrary to PEP8.  E731 is silly.
-ignore = W503,E203,E731
-
 [flake8]
-# note that flake8 inherits the "ignore" settings from "pep8" (because it uses
-# pep8 to do those checks), but not the "max-line-length" setting
 max-line-length = 90
-ignore=W503,E203,E731
+
+# see https://pycodestyle.readthedocs.io/en/latest/intro.html#error-codes
+# for error codes. The ones we ignore are:
+#  W503: line break before binary operator
+#  W504: line break after binary operator
+#  E203: whitespace before ':' (which is contrary to pep8?)
+#  E731: do not assign a lambda expression, use a def
+ignore=W503,W504,E203,E731
 
 [isort]
 line_length = 89