errors running msvnstats.py

[Kamal Ahmed]

/home/kahmed/msvnstats.py -i subversionlog.xml -o /home/kahmed/

/home/kahmed/msvnstats.py:288: SyntaxWarning: assertion is always true, perhaps remove parentheses?
  assert(isinstance(self._title, basestring), 'Title of the statistic must be specified!')
/home/kahmed/msvnstats.py:1929: SyntaxWarning: assertion is always true, perhaps remove parentheses?
  assert(isinstance(action, str) and len(action) == 1,
/home/kahmed/msvnstats.py:1931: SyntaxWarning: assertion is always true, perhaps remove parentheses?
  assert(isinstance(path, basestring), 'should be modified path, is: %s' % path)
Python Imagin Library could not be found - graphs are disabled.
Traceback (most recent call last):
  File "/home/kahmed/msvnstats.py", line 2185, in <module>
    main(sys.argv)
  File "/home/kahmed/msvnstats.py", line 79, in main
    stats = AllStatistics(config)
  File "/home/kahmed/msvnstats.py", line 811, in __init__
    self.append(CommitsGroup(config))
  File "/home/kahmed/msvnstats.py", line 1058, in __init__
    SimpleFunctionGroup.__init__(self, config, 'commits_group', 'Number of commits')
  File "/home/kahmed/msvnstats.py", line 1028, in __init__
    self.append(self.SimpleMultiAuthorGraphStatistic(config, self))
  File "/home/kahmed/msvnstats.py", line 917, in __init__
    "Graph for most active commiters")
  File "/home/kahmed/msvnstats.py", line 542, in __init__
    self._set_writer('html', GraphImageHTMLWriter(self))
  File "/home/kahmed/msvnstats.py", line 1490, in __init__
    self.font = ImageFont.load_default()
NameError: global name 'ImageFont' is not defined