Series.
tshift
Shift the time index, using the index’s frequency if available.
Number of periods to move, can be positive or negative.
Increment to use from the tseries module or time rule expressed as a string (e.g. ‘EOM’).
Corresponds to the axis that contains the Index.
Notes
If freq is not specified then tries to use the freq or inferred_freq attributes of the index. If neither of those attributes exist, a ValueError is thrown