Fix: positional argument specifiers are required by Python 2.6

cgohlke · cgohlke · commit 9ed51ec221a2 · 2012-12-11T23:20:56.000-08:00
diff --git a/lib/matplotlib/backends/backend_wx.py b/lib/matplotlib/backends/backend_wx.py
@@ -1254,7 +1254,7 @@ def _get_key(self, evt):
                              [evt.AltDown, 'alt'],
                              [evt.ControlDown, 'ctrl'], ):
             if meth():
-                key = '{}+{}'.format(prefix, key)
+                key = '{0}+{1}'.format(prefix, key)
 
         return key
 
