DataFrame.at_time(time, asof=False)

Panel4D.notnull()

Panel4D.keys()

CategoricalIndex.get_value(series, key)

CategoricalIndex.ndim return the number of dimensions of the underlying data, by definition 1

Series.plot.area(**kwds)

Panel4D.apply(func, axis='major', **kwargs)

Series.is_monotonic_increasing Return boolean if values in the object are monotonic_increasing

Panel.groupby(function, axis='major')

DataFrame.radd(other, axis='columns', level=None, fill_value=None)