Best way to create list [ [1,2,3], [4,5,6] ] in Python

I want to generate the list of list [[1,2,3],[4,5,6]]

I have attached some python codes but I do not know what to pick among them in terms of efficiency:

[[y + x for x in range(3)] for y in [1,4]]
[[y for y in range(z, z + 3)] for z in [1,4]]
[[y, y + 1, y + 2] for y in [1,4]]

They all generate the required list however I do not feel satisfied with how they are written (since they are all dependent on getting values from the list [1,4]) and considering that I am only a beginner in the Python language. Can you also recommend me a good way to generate the list required? Thank you

>Solution :

[[y + x for x in range(3)] for y in [1,4]]

In this code, Giving the value 4 is not the best way because in order to print a list like this

[[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12], [13, 14, 15], [16, 17, 18], [19, 20, 21], [22, 23, 24], [25, 26, 27], [28, 29, 30]]

you might have to write

[[y + x for x in range(3)] for y in [1,4,7,10,13,16,19,22,25,28]]

which is not an easy and generalised code.Instead you can write

[[ x for x in range(y,y+3)] for y in range(1,6,3)]

or

[[ x for x in range(y,y+3)] for y in range(1,n,3)]