Traceback (most recent call last):
  File "/usr/sbin/update-apt-xapian-index", line 102, in <module>
    indexer.incrementalUpdate()
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 669, in incrementalUpdate
    self.updateIndex(dbpath)
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 629, in updateIndex
    cache = self.aptcache()
  File "/usr/lib/python2.7/dist-packages/axi/indexer.py", line 418, in aptcache
    self.apt_cache = apt.Cache(memonly=True, progress=aptprogress)
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 93, in __init__
    self.open(progress)
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 136, in open
    self._cache = apt_pkg.Cache(progress)
SystemError: E:Malformed line 56 in source list /etc/apt/sources.list (dist parse), E:The list of sources could not be read., E:The package lists or status file could not be parsed or opened.