Ignore new flake8 errors.

setup.cfg

@@ -10,7 +10,7 @@ all_files = 1
 [flake8]
 # classes can be lowercase, arguments and variables can be uppercase
 # whenever it makes the code more readable.
-ignore = N806, N802, N801, N803
+ignore = N806, N802, N801, N803, E741, E742, E722
 
 [pep257]
 ignore = D102,D104,D203,D105,D213