Remove 2.6 workaround for missing WeakSet

jenshnielsen · jenshnielsen · commit b8eb2d8d59bd · 2015-10-31T10:37:47.000Z
diff --git a/lib/matplotlib/backends/backend_pgf.py b/lib/matplotlib/backends/backend_pgf.py
@@ -235,31 +235,14 @@ def get_latex_manager():
             LatexManagerFactory.previous_instance = new_inst
             return new_inst
 
-class WeakSet(object):
-    # TODO: Poor man's weakref.WeakSet.
-    #       Remove this once python 2.6 support is dropped from matplotlib.
-
-    def __init__(self):
-        self.weak_key_dict = weakref.WeakKeyDictionary()
-
-    def add(self, item):
-        self.weak_key_dict[item] = None
-
-    def discard(self, item):
-        if item in self.weak_key_dict:
-            del self.weak_key_dict[item]
-
-    def __iter__(self):
-        return six.iterkeys(self.weak_key_dict)
-
 
 class LatexManager(object):
     """
     The LatexManager opens an instance of the LaTeX application for
     determining the metrics of text elements. The LaTeX environment can be
     modified by setting fonts and/or a custem preamble in the rc parameters.
     """
-    _unclean_instances = WeakSet()
+    _unclean_instances = weakref.WeakSet()
 
     @staticmethod
     def _build_latex_header():
