lists are very powerful, the elements can be everything you want, including another list

Other operations of list:
1. Append
  like a procedure, but its a method.
  will add a new element to the end of list
  not creating a new list, but mutating the old list

<list>.append(<element>)
[1,2].append([3,4]) → [1,2,[3,4]]

2. Plus
  <list> + <list>
  [0,1] + [2,3] = [0,1,2,3]
#be careful about the deffernce between append and plus
3. len
  len(<list>)
  len also works for strings
  len(['a',['b',['c']]]) → 2