Return uniformly-distributed dates in 2014.

def _datetime_values(self, shape):
        """
        Return uniformly-distributed dates in 2014.
        """
        start = Timestamp('2014', tz='UTC').asm8
        offsets = self.state.randint(
            low=0,
            high=364,
            size=shape,
        ).astype('timedelta64[D]')
        return start + offsets