Python Array Inside An Array

I'm not sure if this is common knowledge or not but you can store data in Python with as many arrays inside other arrays as you want.

test = [[1, 2, 3], [4, 5, 6], [7, 8, [9, 10]]]  
print test[2][2][0]  

>>>9

print test[0]  

>>>[1, 2, 3]

print test[0][1]  

>>>2

Just something I thought was cool.