diff --git a/msrp/tls.py b/msrp/tls.py
index 4acfd2c..feaefa9 100644
--- a/msrp/tls.py
+++ b/msrp/tls.py
@@ -1,47 +1,48 @@
 
 __all__ = ['Certificate', 'PrivateKey']
 
 from gnutls.crypto import X509Certificate, X509PrivateKey
 
 from application.process import process
 
 class _FileError(Exception): pass
 
+
 def file_content(file):
     path = process.config_file(file)
     if path is None:
         raise _FileError("File '%s' does not exist" % file)
     try:
         f = open(path, 'rt')
     except:
         raise _FileError("File '%s' could not be open" % file)
     try:
         return f.read()
     finally:
         f.close()
 
+
 class Certificate(object):
     """Configuration data type. Used to create a gnutls.crypto.X509Certificate object
        from a file given in the configuration file."""
-    def __new__(typ, value):
+    def __new__(cls, value):
         if isinstance(value, str):
             try:
                 return X509Certificate(file_content(value))
             except Exception, e:
                 raise ValueError("Certificate file '%s' could not be loaded: %s" % (value, str(e)))
-                return None
         else:
-            raise TypeError, 'value should be a string'
+            raise TypeError('value should be a string')
+
 
 class PrivateKey(object):
     """Configuration data type. Used to create a gnutls.crypto.X509PrivateKey object
        from a file given in the configuration file."""
-    def __new__(typ, value):
+    def __new__(cls, value):
         if isinstance(value, str):
             try:
                 return X509PrivateKey(file_content(value))
             except Exception, e:
                 raise ValueError("Private key file '%s' could not be loaded: %s" % (value, str(e)))
-                return None
         else:
-            raise TypeError, 'value should be a string'
+            raise TypeError('value should be a string')