def _add_nat(self):
if is_period_dtype(self):<EOL><INDENT>raise TypeError('<STR_LIT>'<EOL>.format(cls=type(self).__name__,<EOL>typ=type(NaT).__name__))<EOL><DEDENT>result = np.zeros(len(self), dtype=np.int64)<EOL>result.fill(iNaT)<EOL>return type(self)(result, dtype=self.dtype, freq=None)<EOL>
Add pd.NaT to self