def diff(self, n, axis=<NUM_LIT:0>):
if axis == <NUM_LIT:0>:<EOL><INDENT>raise NotImplementedError<EOL><DEDENT>new_values = (self.values - self.shift(n, axis=axis)[<NUM_LIT:0>].values).asi8<EOL>new_values = new_values.reshape(<NUM_LIT:1>, len(new_values))<EOL>new_values = new_values.astype('<STR_LIT>')<EOL>return [TimeDeltaBlock(new_values, placement=self.mgr_locs.indexer)]<EOL>
1st discrete difference

        Parameters
        ----------
        n : int, number of periods to diff
        axis : int, axis to diff upon. default 0

        Return
        ------
        A list with a new TimeDeltaBlock.

        Note
        ----
        The arguments here are mimicking shift so they are called correctly
        by apply.