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 the default depth of 1, will output the list [['b','c'], ['f','g'],['j','k'],['n','o'']] as it is the list with depth 1 e.g. ['e','f','g','h'] that are considered.