Python Faster 'If' Usage

I have a list:

a = [1, 2, 3, 4, 5, 6, 7, 8, 9 10, 11, 12]

There are multiple if usages that check a number is in the a list. Whole code is also in a loop.

If 3 in a:
    some_work1

If 4 in a:
    some_work2

If 8 in a:
    some_work3

If 11 in a:
    some_work4

Are there faster any (less cpu usage) methods for these multiple if usages? (List a is always same).

Python 3.8.7