[Python][Resolved] TypeError: unhashable type: 'list'

 I want to convert a 2 dimensional list to a set with set(), but it got a type error:

>>> list1 = [[1,2,3],[2,5,6],[7,8,9]]
>>> type(list1)
<class 'list'>
>>> set1 = set(list1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'

I found it's needed to change syntax to create your list

>>> list2 = [(1,2,3),(2,5,6),(7,8,9)]
>>> type(list2)
<class 'list'>
>>> set2 = set(list2)
>>> set2
{(7, 8, 9), (2, 5, 6), (1, 2, 3)}