--- a/dataimport/deprecated.py	Fri Sep 11 14:52:09 2015 +0200
+++ b/dataimport/deprecated.py	Fri Sep 11 15:29:25 2015 +0200
@@ -167,7 +167,9 @@
                 if res[dest] is None:
                     break
         except ValueError as err:
-            raise ValueError('error with %r field: %s' % (src, err)), None, sys.exc_info()[-1]
+            exc = ValueError('error with %r field: %s' % (src, err))
+            exc.__traceback__ = sys.exc_info()[-1]
+            raise exc
     return res
 
 

--- a/devtools/testlib.py	Fri Sep 11 14:52:09 2015 +0200
+++ b/devtools/testlib.py	Fri Sep 11 15:29:25 2015 +0200
@@ -940,7 +940,9 @@
                 msg = '[%s in %s] %s' % (klass, view.__regid__, exc)
             except Exception:
                 msg = '[%s in %s] undisplayable exception' % (klass, view.__regid__)
-            raise AssertionError, msg, tcbk
+            exc = AssertionError(msg)
+            exc.__traceback__ = tcbk
+            raise exc
         return self._check_html(output, view, template)
 
     def get_validator(self, view=None, content_type=None, output=None):
@@ -1015,7 +1017,9 @@
                                          for idx, line in enumerate(content)
                                          if line_context_filter(idx+1, position))
                     msg += u'\nfor content:\n%s' % content
-            raise AssertionError, msg, tcbk
+            exc = AssertionError(msg)
+            exc.__traceback__ = tcbk
+            raise exc
 
     def assertDocTestFile(self, testfile):
         # doctest returns tuple (failure_count, test_count)

--- a/ext/tal.py	Fri Sep 11 14:52:09 2015 +0200
+++ b/ext/tal.py	Fri Sep 11 15:29:25 2015 +0200
@@ -184,7 +184,10 @@
             interpreter.execute(self)
         except UnicodeError as unierror:
             LOGGER.exception(str(unierror))
-            raise simpleTALES.ContextContentException("found non-unicode %r string in Context!" % unierror.args[1]), None, sys.exc_info()[-1]
+            exc = simpleTALES.ContextContentException(
+                "found non-unicode %r string in Context!" % unierror.args[1])
+            exc.__traceback__ = sys.exc_info()[-1]
+            raise exc
 
 
 def compile_template(template):
@@ -232,7 +235,8 @@
         result = eval(expr, globals, locals)
     except Exception as ex:
         ex = ex.__class__('in %r: %s' % (expr, ex))
-        raise ex, None, sys.exc_info()[-1]
+        ex.__traceback__ = sys.exc_info()[-1]
+        raise ex
     if (isinstance (result, simpleTALES.ContextVariable)):
         return result.value()
     return result

--- a/gettext.py	Fri Sep 11 14:52:09 2015 +0200
+++ b/gettext.py	Fri Sep 11 15:29:25 2015 +0200
@@ -103,11 +103,10 @@
     try:
         danger = [x for x in tokens if x[0] == token.NAME and x[1] != 'n']
     except tokenize.TokenError:
-        raise ValueError, \
-              'plural forms expression error, maybe unbalanced parenthesis'
+        raise ValueError('plural forms expression error, maybe unbalanced parenthesis')
     else:
         if danger:
-            raise ValueError, 'plural forms expression could be dangerous'
+            raise ValueError('plural forms expression could be dangerous')
 
     # Replace some C operators by their Python equivalents
     plural = plural.replace('&&', ' and ')
@@ -133,7 +132,7 @@
                 # Actually, we never reach this code, because unbalanced
                 # parentheses get caught in the security check at the
                 # beginning.
-                raise ValueError, 'unbalanced parenthesis in plural form'
+                raise ValueError('unbalanced parenthesis in plural form')
             s = expr.sub(repl, stack.pop())
             stack[-1] += '(%s)' % s
         else:

--- a/web/http_headers.py	Fri Sep 11 14:52:09 2015 +0200
+++ b/web/http_headers.py	Fri Sep 11 15:29:25 2015 +0200
@@ -295,9 +295,9 @@
         cur = cur+1
 
     if qpair:
-        raise ValueError, "Missing character after '\\'"
+        raise ValueError("Missing character after '\\'")
     if quoted:
-        raise ValueError, "Missing end quote"
+        raise ValueError("Missing end quote")
 
     if start != cur:
         if foldCase:
@@ -347,7 +347,7 @@
 ##### parser utilities:
 def checkSingleToken(tokens):
     if len(tokens) != 1:
-        raise ValueError, "Expected single token, not %s." % (tokens,)
+        raise ValueError("Expected single token, not %s." % (tokens,))
     return tokens[0]
 
 def parseKeyValue(val):
@@ -355,7 +355,7 @@
         return val[0], None
     elif len(val) == 3 and val[1] == Token('='):
         return val[0], val[2]
-    raise ValueError, "Expected key or key=value, but got %s." % (val,)
+    raise ValueError("Expected key or key=value, but got %s." % (val,))
 
 def parseArgs(field):
     args = split(field, Token(';'))
@@ -506,7 +506,7 @@
     type, args = parseArgs(field)
 
     if len(type) != 3 or type[1] != Token('/'):
-        raise ValueError, "MIME Type "+str(type)+" invalid."
+        raise ValueError("MIME Type "+str(type)+" invalid.")
 
     # okay, this spec is screwy. A 'q' parameter is used as the separator
     # between MIME parameters and (as yet undefined) additional HTTP
@@ -569,7 +569,7 @@
     type, args = parseArgs(header)
 
     if len(type) != 3 or type[1] != Token('/'):
-        raise ValueError, "MIME Type "+str(type)+" invalid."
+        raise ValueError("MIME Type "+str(type)+" invalid.")
 
     args = [(kv[0].lower(), kv[1]) for kv in args]
 

--- a/web/views/baseviews.py	Fri Sep 11 14:52:09 2015 +0200
+++ b/web/views/baseviews.py	Fri Sep 11 15:29:25 2015 +0200
@@ -231,7 +231,7 @@
         """
         rset = self.cw_rset
         if rset is None:
-            raise NotImplementedError, self
+            raise NotImplementedError(self)
         for i in xrange(len(rset)):
             self.wview(self.__regid__, rset, row=i, **kwargs)
             if len(rset) > 1: