[Checkins] [zopefoundation/BTrees] dfde59: Error handling improvements.

[Jason Madden]

  Branch: refs/heads/issue120
  Home:   https://github.com/zopefoundation/BTrees
  Commit: dfde5933d0453ffecbd4076ccd94cd3b5bdf2540
      https://github.com/zopefoundation/BTrees/commit/dfde5933d0453ffecbd4076ccd94cd3b5bdf2540
  Author: Jason Madden <jamadden at gmail.com>
  Date:   2020-02-14 (Fri, 14 Feb 2020)

  Changed paths:
    M .travis.yml
    M BTrees/BTreeModuleTemplate.c
    M BTrees/SetOpTemplate.c
    M BTrees/_base.py
    M BTrees/tests/testBTrees.py
    M CHANGES.rst

  Log Message:
  -----------
  Error handling improvements.

Also, BTreeModuleTemplate.c was a terrible mixed mess of tabs and spaces.