def path_shift(self, shift=<NUM_LIT:1>):
script = self.environ.get('<STR_LIT>','<STR_LIT:/>')<EOL>self['<STR_LIT>'], self['<STR_LIT>'] = path_shift(script, self.path, shift)<EOL>
Shift path segments from :attr:`path` to :attr:`script_name` and
            vice versa.

           :param shift: The number of path segments to shift. May be negative
                         to change the shift direction. (default: 1)