diff --git a/setup.py b/setup.py
index d11b75c..b7e88c7 100644
--- a/setup.py
+++ b/setup.py
@@ -13,12 +13,17 @@ class DisabledTestCommand(Command):
 	def __init__(self, dist):
 		raise RuntimeError("test command not supported on svg.charts. Use setup.py nosetests instead")
 
+try:
+	from distutils.command.build_py import build_py_2to3 as build_py
+except ImportError:
+	from distutils.command.build_py import build_py
+
 _this_dir = os.path.dirname(__file__)
 _long_description = open('readme.txt').read().strip()
 
 # it seems that dateutil 2.0 only works under Python 3
 dateutil_req = (
-	['python-dateutil>=1.4,<2.0dev'] if sys.version < (3,0)
+	['python-dateutil>=1.4,<2.0dev'] if sys.version_info < (3,0)
 	else ['python-dateutil>=2.0'] )
 
 setup_params = dict(
@@ -51,6 +56,7 @@ setup_params = dict(
 	# see http://code.google.com/p/python-nose/issues/detail?id=219
 	cmdclass=dict(
 		test=DisabledTestCommand,
+		build_py=build_py,
 	),
 )
 
diff --git a/svg/charts/graph.py b/svg/charts/graph.py
index ef29b0a..84d96a0 100644
--- a/svg/charts/graph.py
+++ b/svg/charts/graph.py
@@ -91,7 +91,7 @@ class Graph(object):
 	def __init__(self, config = {}):
 		"""Initialize the graph object with the graph settings."""
 		if self.__class__ is Graph:
-			raise NotImplementedError, "Graph is an abstract base class"
+			raise NotImplementedError("Graph is an abstract base class")
 		self.load_config(config)
 		self.clear_data()
 		self.style = {}
diff --git a/svg/charts/plot.py b/svg/charts/plot.py
index 7729c3b..19affc8 100644
--- a/svg/charts/plot.py
+++ b/svg/charts/plot.py
@@ -262,8 +262,9 @@ class Plot(Graph):
 		if hasattr(self, 'constant_lines'):
 			map(self.__draw_constant_line, self.constant_lines)
 
-	def __draw_constant_line(self, (value, label, style)):
+	def __draw_constant_line(self, value_label_style):
 		"Draw a constant line on the y-axis with the label"
+		value, label, style = value_label_style
 		start = self.transform_output_coordinates((0, value))[1]
 		stop = self.graph_width
 		path = etree.SubElement(self.graph, 'path', {