purge.lm                Purges mediator effects between two independent
                        variables (linear)
purge.logit             Purges mediator effects between two independent
                        variables (logit link function)
purge.negbin            Purges mediator effects between two independent
                        variables (negative binomial)
purge.poisson           Purges mediator effects between two independent
                        variables (Poisson)
purge.probit            Purges mediator effects between two independent
                        variables (probit link function)
