how to make the list to start append from last code example

Example 1: add a value to the start of a list python

>>>var=7
>>>array = [1,2,3,4,5,6]
>>>array.insert(0,var)
>>>array
[7, 1, 2, 3, 4, 5, 6]

Example 2: python add all values of another list

a = [1, 2, 3]
b = [4, 5, 6]
a += b
# another way: a.extend(b)