#append to list
lst = [1, 2, 3]
li = 4
lst.append(li)
#lst is now [1, 2, 3, 4]
.append("the add"): append the object to the end of the list.
.insert("the add"): inserts the object before the given index.
.extend("the add"): extends the list by appending elements from the iterable.