def __init__(self, changeSpec=None, *args, **kw):
self.baseline = []<EOL>self.current  = []<EOL>super(ListChangeTracker, self).__init__(changeSpec, *args, **kw)<EOL>
Initializes this ListChangeTracker with the provided `changeSpec`,
which is expected to be in the same format as what would have been
returned by a call to ``str()`` on this object. The change-spec
will look similar to::

  2:a,1:M68b329d...,1:mh4d9,2:Dba45...,3:a

If `changeSpec` is not specified, this ListChangeTracker will
start assuming no prior changes were made to any content and will
expect changes to be reported via :meth:`pushChange`.