Pulled natural sorting methods out from the try (no real reason for them to be in there) and moved "try_int" to outside the other method (then it is only compiled once).

setup.py

@@ -31,15 +31,8 @@ from setuptools import setup, find_packages
 import re
 
 VERSION_FILE = 'openlp/.version'
+SPLIT_ALPHA_DIGITS = re.compile(r'(\d+|\D+)')
 
-try:
-    def natural_sort_key(s):
-        """
-        Return a tuple by which s is sorted.
-
-        ``s``
-            A string value from the list we want to sort.
-        """
 def try_int(s):
     """
     Convert string s to an integer if possible. Fail silently and return
@@ -50,9 +43,17 @@ try:
     """
     try:
         return int(s)
-            except:
+    except Exception:
         return s
-        return map(try_int, re.findall(r'(\d+|\D+)', s))
+
+def natural_sort_key(s):
+    """
+    Return a tuple by which s is sorted.
+
+    ``s``
+        A string value from the list we want to sort.
+    """
+    return map(try_int, SPLIT_ALPHA_DIGITS.findall(s))
 
 def natural_compare(a, b):
     """
@@ -75,6 +76,8 @@ try:
     temp.sort(compare)
     return temp
 
+try:
+    # Try to import Bazaar
     from bzrlib.branch import Branch
     b = Branch.open_containing('.')[0]
     b.lock_read()