Comment 7 for bug 1444269

The hash() is a built-in python method, used to return a unique number . This can be applied to any user-defined object which won’t get changed once initialized. This property is used mainly in dictionary keys .

TypeError: unhashable type: 'list' usually means that you are trying to use a list as an hash argument. This means that when you try to hash an unhashable object it will result an error. For ex. when you use a list as a key in the dictionary , this cannot be done because lists can't be hashed. The standard way to solve this issue is to cast a list to a tuple .

http://net-informations.com/python/iq/unhashable.htm