Function for Plotting PSC objects
# S3 method for psc.flexsurvreg
plot(pscOb, addFit = T, ...)a survival plot corresponding to the psc fit
an object of class 'psc'
should a curve for the model fit be added?
not used
making use of 'ggsurvplot' in the survminer package, this function plots the expected survival funtion for the 'control' treatment estimated from the CFM along with the Kaplan Meier estimates of the observed events