Determine if the object is a valid site_model
See also
A site model can be created using create_site_model
Examples
check_empty_beautier_folder()
# TRUE
is_site_model(create_gtr_site_model())
#> [1] TRUE
is_site_model(create_hky_site_model())
#> [1] TRUE
is_site_model(create_jc69_site_model())
#> [1] TRUE
is_site_model(create_tn93_site_model())
#> [1] TRUE
# FALSE
is_site_model(NA)
#> [1] FALSE
is_site_model(NULL)
#> [1] FALSE
is_site_model("nonsense")
#> [1] FALSE
is_site_model(create_strict_clock_model())
#> [1] FALSE
is_site_model(create_bd_tree_prior())
#> [1] FALSE
is_site_model(create_mcmc())
#> [1] FALSE
check_empty_beautier_folder()