GroupBy.nth(n, dropna=None)

DatetimeIndex.dropna(how='any')

DatetimeIndex.is_numeric()

DatetimeIndex.tolist()

DatetimeIndex.is_all_dates

DatetimeIndex.values return the underlying data as an ndarray

Series.count(level=None)

TimedeltaIndex.inferred_freq = None

DatetimeIndex.max(axis=None, *args, **kwargs)

GroupBy.groups dict {group name -> group labels}