The three artifacts a split is carried in, and the digest that says
two arrays are the same array.
write_folds()
Write a fold map as id,fold, ordered by unit.
read_folds()
read_folds(file, units=None)
Read a fold map somebody else built, optionally aligned to a
representation’s units.
write_response()
write_response(y: Response, file)
Write a response as id and one column per variable,
ordered by unit.
read_response()
read_response(file, units=None)
Read a response matrix. The columns after id are the
variables, in the file’s order.
write_cells()
write_cells(cells: Cells, file)
Write a scorable mask, ordered by variable and then by fold.
read_cells()
Read a scorable mask the other language computed.
digest_array()
MD5 of the representation, byte-exactly as the spec defines it.