Graph.to_string function broken

This bug was fixed in the package pydot - 1.0.28-0ubuntu1

---------------
pydot (1.0.28-0ubuntu1) trusty; urgency=low

  * New upstream release. (LP: #574428, #987934)
  * debian/control updated to newest standards version:
    - Removed DM-Upload-Allowed, obsolete
    - Updated Vsc-Browser field
    - Depend on python-setuptools
    - Depend on pyparsing >= 2.0.1 to prevent incompability problems with
      debian/patches/03-support-pyparsing-v2.patch
    - Add ${misc:Depends} to binary package Depends
    - Support dh-python
      o Bumped cdbs version to 0.4.90
      o Bumped python version to 2.6.6.3
      o Removed XB-Python-Version field
      o Added X-Python-Version field
      o Removed ${python:Depends} from Depends
  * debian/rules:
    - do not include simple-patchsys.mk
    - Support dh-python: Remove DEB_PYTHON_SYSTEM
  * debian/pyversions: not required for dh-python
  * debian/pycompat: not required for dh-python
  * debian/source/format: added and set to 3.0 (quilt)
  * debian/patches/02-use-setuptools.patch: patched setup.py to use setuptools
    to prevent "Unknown distribution option: 'install_requires'" warning
  * debian/patches/03-support-pyparsing-v2.patch: add support for pyparsing
    version 2.X, fixes "Couldn't import dot_parser" error
 -- Maarten Bezemer <email address hidden> Sat, 15 Feb 2014 14:01:16 +0100