diff --git a/.travis.yml b/.travis.yml
index 86d3188e983..8e639e3e2e1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -139,7 +139,8 @@ script:
       deactivate
       source ~/virtualenv/python2.7/bin/activate
       pip install pip --upgrade
-      pip install linkchecker
+      # linkchecker is currently broken with requests 2.10.0 so force an earlier version
+      pip install $PRE requests==2.9.2 linkchecker
       linkchecker build/html/index.html
     fi
   - rm -rf $HOME/.cache/matplotlib/tex.cache
diff --git a/lib/matplotlib/animation.py b/lib/matplotlib/animation.py
index f1e2420499b..b53d25a9249 100644
--- a/lib/matplotlib/animation.py
+++ b/lib/matplotlib/animation.py
@@ -1217,8 +1217,8 @@ class FuncAnimation(TimedAnimation):
     results of drawing from the first item in the frames sequence will be
     used. This function will be called once before the first frame.
 
-    If blit=True, *func* and *init_func* should return an iterable of
-    drawables to clear.
+    If blit=True, *func* and *init_func* must return an iterable of
+    artists to be re-drawn.
 
     *kwargs* include *repeat*, *repeat_delay*, and *interval*:
     *interval* draws a new frame every *interval* milliseconds.
@@ -1299,6 +1299,9 @@ def _init_draw(self):
         else:
             self._drawn_artists = self._init_func()
             if self._blit:
+                if self._drawn_artists is None:
+                    raise RuntimeError('The init_func must return a '
+                                       'sequence of Artist objects.')
                 for a in self._drawn_artists:
                     a.set_animated(self._blit)
         self._save_seq = []
@@ -1315,5 +1318,8 @@ def _draw_frame(self, framedata):
         # func needs to return a sequence of any artists that were modified.
         self._drawn_artists = self._func(framedata, *self._args)
         if self._blit:
+            if self._drawn_artists is None:
+                    raise RuntimeError('The animation function must return a '
+                                       'sequence of Artist objects.')
             for a in self._drawn_artists:
                 a.set_animated(self._blit)
diff --git a/lib/matplotlib/backends/backend_ps.py b/lib/matplotlib/backends/backend_ps.py
index 2f8ffaeaf65..256c9f8c125 100644
--- a/lib/matplotlib/backends/backend_ps.py
+++ b/lib/matplotlib/backends/backend_ps.py
@@ -165,15 +165,16 @@ def _num_to_str(val):
 def _nums_to_str(*args):
     return ' '.join(map(_num_to_str,args))
 
+
 def quote_ps_string(s):
     "Quote dangerous characters of S for use in a PostScript string constant."
-    s=s.replace("\\", "\\\\")
-    s=s.replace("(", "\\(")
-    s=s.replace(")", "\\)")
-    s=s.replace("'", "\\251")
-    s=s.replace("`", "\\301")
-    s=re.sub(r"[^ -~\n]", lambda x: r"\%03o"%ord(x.group()), s)
-    return s
+    s = s.replace(b"\\", b"\\\\")
+    s = s.replace(b"(", b"\\(")
+    s = s.replace(b")", b"\\)")
+    s = s.replace(b"'", b"\\251")
+    s = s.replace(b"`", b"\\301")
+    s = re.sub(br"[^ -~\n]", lambda x: br"\%03o" % ord(x.group()), s)
+    return s.decode('ascii')
 
 
 def seq_allequal(seq1, seq2):
diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
index 38b9dafec89..578a5a2a5ab 100644
--- a/lib/matplotlib/rcsetup.py
+++ b/lib/matplotlib/rcsetup.py
@@ -760,17 +760,16 @@ def validate_cycler(s):
             # might come from the internet (future plans), this
             # could be downright dangerous.
             # I locked it down by only having the 'cycler()' function
-            # available. Imports and defs should not
-            # be possible. However, it is entirely possible that
-            # a security hole could open up via attributes to the
-            # function (this is why I decided against allowing the
-            # Cycler class object just to reduce the number of
-            # degrees of freedom (but maybe it is safer to use?).
-            # One possible hole I can think of (in theory) is if
-            # someone managed to hack the cycler module. But, if
-            # someone does that, this wouldn't make anything
-            # worse because we have to import the module anyway.
-            s = eval(s, {'cycler': cycler})
+            # available.
+            # UPDATE: Partly plugging a security hole.
+            # I really should have read this:
+            # http://nedbatchelder.com/blog/201206/eval_really_is_dangerous.html
+            # We should replace this eval with a combo of PyParsing and
+            # ast.literal_eval()
+            if '.__' in s.replace(' ', ''):
+                raise ValueError("'%s' seems to have dunder methods. Raising"
+                                 " an exception for your safety")
+            s = eval(s, {'cycler': cycler, '__builtins__': {}})
         except BaseException as e:
             raise ValueError("'%s' is not a valid cycler construction: %s" %
                              (s, e))
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
index c6a55471f95..aec2fee307f 100644
--- a/lib/matplotlib/ticker.py
+++ b/lib/matplotlib/ticker.py
@@ -135,6 +135,9 @@
 :class:`EngFormatter`
     Format labels in engineering notation
 
+:class:`EngFormatter`
+    Format labels in engineering notation
+
 :class:`PercentFormatter`
     Format labels as a percentage