Checks that the censoring formula is valid, uses Surv() notation, and extracts the time and event variable names.
validate_censor_formula(censor_formula)A list containing:
The validated formula object, or NULL if RHS is 0 (no censoring adjustment)
Character string of the time variable name
Character string of the event variable name
A formula object for the censoring model. Should be of the form `Surv(time, event) ~ covariates`. Use `Surv(time, event) ~ 0` to indicate no censoring adjustment (all censoring scores set to 1).