a sequence of sequences of strings representing the descriptions
of all rows. The outer index represents different rows.
The inner index represents the different levels (usually there is only one).
a sequence of sequences of strings representing the descriptions of all
rows. The outer index represents different rows.
The inner index represents the different levels (usually there is only one).
a sequence of sequences of strings representing the descriptions
of all columns. The outer index represents different columns.
The inner index represents the different levels (usually there is only one).
a sequence of sequences of strings which represent the descriptions of
all columns. The outer index represents different columns.
The inner index represents the different levels (usually there is only one).