AttributeError: type object 'LedgerTransactionView' has no attribute 'set_css_name'

[atlet]

When I run addtrans I get following error. How can I fix this error? I'm using Ubuntu.

Traceback (most recent call last):
  File "/usr/local/bin/addtrans", line 4, in <module>
    __import__('pkg_resources').run_script('ledgerhelpers==0.2.3', 'addtrans')
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 719, in run_script
    self.require(requires)[0].run_script(script_name, ns)
  File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 1504, in run_script
    exec(code, namespace, namespace)
  File "/usr/local/lib/python2.7/dist-packages/ledgerhelpers-0.2.3-py2.7.egg/EGG-INFO/scripts/addtrans", line 8, in <module>
    from ledgerhelpers.programs import addtrans
  File "/usr/local/lib/python2.7/dist-packages/ledgerhelpers-0.2.3-py2.7.egg/ledgerhelpers/programs/addtrans.py", line 14, in <module>
    from ledgerhelpers import gui
  File "/usr/local/lib/python2.7/dist-packages/ledgerhelpers-0.2.3-py2.7.egg/ledgerhelpers/gui.py", line 359, in <module>
    LedgerTransactionView.set_css_name("ledgertransactionview")
AttributeError: type object 'LedgerTransactionView' has no attribute 'set_css_name'