The extract_elements_from_a_list is passed the list [['a','b','c', 'd'], ['e','f','g','h'],['i','j','k','l'],['m','n','o','p']] with fromIndex of 1 and toIndex of 3 and depth 2, will output the list [['e','f','g','h'],['i','j','k','l']] as it is the outermost list i.e. that with depth 2 that is considered.