Pseudo Maximum Likelihood Estimation for Semi-Competing Risks Data // Implements two-stage pseudo maximum likelihood estimation (PMLE) for copula-based regression models with semi- competing risks data. The marginal distributions are modeled by semiparametric transformation regression models, and the dependence between bivariate event times is specified by a parametric copula function. See Arachchige, Chen and Zhou (2025) doi:10.1007/s10985-024-09640-z for details.