Get the top classes in the Concept Ancestor table by vocabulary with the option of filtering further for domain.
lookup_top_classes( vocabulary_id, domain_id, vocab_schema = "omop_vocabulary", conn, conn_fun = "chariot::connectAthena()", cache_only = FALSE, skip_cache = FALSE, override_cache = FALSE, cache_resultset = TRUE, render_sql = TRUE, verbose = TRUE, sleepTime = 1 )