'export to a local path
topath should not exist prior to calling this, returns a
py.path.local instance'

def export(self, topath):

    topath = py.path.local(topath)
    args = [('"%s"' % (self._escape(self),)), ('"%s"' % (self._escape(topath),))]
    if (self.rev is not None):
        args = (['-r', str(self.rev)] + args)
    self._svncmdexecauth(('svn    export    %s' % ('    '.join(args),)))
    return topath
