Create new nm object. The function new_nm() is more convenient. This is
mostly a back end function. This is the basic object this package centres
around. Most package functions act on this object.
m0 <- nm(run_id = "m0")
m0 ## a human readable representation## nm objects can be put into tibbles to group runs togetherd <- dplyr::tibble(run_id = c("m1", "m2"))
d$m <- nm(d$run_id)
d