Upsampling returns a Series, Downsampling returns a DataFrame. Is this valid? ``` python In [80]: series=pd.Series(range(10), index=pd.PeriodIndex(start='2000', freq='D', periods=10)) In [81]: series Out[81]: 2000-01-01 0 2000-01-02 1 2000-01-03 2 2000-01-04 3 2000-01-05 4 2000-01-06 5 2000-01-07 6 2000-01-08 7 2000-01-09 8 2000-01-10 9 Freq: D, dtype: int64 In [83]: series.resample('M').ohlc() Out[83]: open high low close 2000-01 0 9 0 9 # returns a DataFrame In [84]: series.resample('H').ohlc() Out[84]: 2000-01-01 00:00 0.0 ... 2000-01-10 23:00 NaN Freq: H, dtype: float64 # returns a series ``` on master