This overrides generic base::merge() to merge two forests into one.
# S3 method for semforest
merge(x, y, ...)
A SEM Forest
A second SEM Forest
Extra arguments. Currently unused.
Brandmaier, A.M., Oertzen, T. v., McArdle, J.J., & Lindenberger, U. (2013). Structural equation model trees. Psychological Methods, 18(1), 71-86.