'Create a ``dict`` of columns from a Pandas GroupBy,
suitable for creating a ColumnDataSource.
The data generated is the result of running ``describe``
on the group.
Args:
data (Groupby) : data to convert
Returns:
dict[str, np.array]'

@classmethod
def from_groupby(cls, data):

    return cls._data_from_df(data.describe())
