title: Stability of .emacs under flycheck
body: <p>To get flycheck working for Python, I had reached a satisfactory <code>.emacs</code>, which turned out to require no more than:</p>
  
  <pre><code>(require 'flycheck)
  (add-hook 'after-init-hook #'global-flycheck-mode)
  </code></pre>
  
  <p>Now after a bit of looking <a href="https://stackoverflow.com/q/46079912/704972">forward</a> at what Python 3.6 will be like, even a two-liner</p>
  
  <pre><code>class Foo():
      pass
  </code></pre>
  
  <p>gets a whole slew of warnings:</p>
  
  <pre><code>Too few public methods (0/2) [too-few-public-methods]
  Class has no __init__ method [no-init]
  Old-style class defined. [old-style-class]
  Missing class docstring [missing-docstring]
  Missing module docstring [missing-docstring]
  </code></pre>
  
  <p>despite that I'm now firmly back in 2.7 (<code>sudo port select --set python python27</code>).</p>
  
  <p>Emacs gets us used to being context-agnostic. It usually doesn't matter what is on the system; one gets the same behavior if one starts from an unchanged <code>.emacs</code>. What else might have changed in my system to trigger a sudden increase in flycheck warnings?</p>