use condition rather than try/catch

cps/helper.py

@@ -245,9 +245,9 @@ def get_valid_filename(value, replace_whitespace=True):
         value=value.replace(u'ß',u'ss')
         value = unicodedata.normalize('NFKD', value)
         re_slugify = re.compile('[\W\s-]', re.UNICODE)
-        try:
+        if type(value) is str: #Python3 str, Python2 unicode
-            value = str(re_slugify.sub('', value).strip())
+            value = re_slugify.sub('', value).strip()
-        except UnicodeEncodeError as e: #will exception on Python2.7
+        else:
             value = unicode(re_slugify.sub('', value).strip())
     if replace_whitespace:
         #*+:\"/<>? werden durch _ ersetzt

cps/web.py

@@ -1052,8 +1052,10 @@ def stats():
                              stdin=subprocess.PIPE)
         p.wait()
         for lines in p.stdout.readlines():
-            if re.search('Amazon kindlegen\(', str(lines)):
+            if type(lines) is bytes:
-                versions['KindlegenVersion'] = str(lines)
+                lines = lines.decode('utf-8')
+            if re.search('Amazon kindlegen\(', lines):
+                versions['KindlegenVersion'] = lines
     versions['PythonVersion'] = sys.version
     versions['babel'] = babelVersion
     versions['sqlalchemy'] = sqlalchemyVersion