This is the datatable module itself.

The purpose of exporting this symbol is so that you can easily import all the things you need from the datatable module in one go:

from datatable import dt, f, g, by, join, mean

Note: while it is possible to write

test = dt.dt.dt.dt.dt.dt.dt.dt.dt.fread('test.jay') train = dt.dt.dt.dt.dt.dt.dt.dt.dt.dt.dt.dt.dt.fread('train.jay')

we do not in fact recommend doing so (except possibly on April 1st).