How can I do the following in Python?

a = [2,[33,4],[2,3,4,6]]
li = [ i for i in a if isinstance(i,int) else j in i ]

how do i convert list a into a = [2,33,4,2,3,4,6]

I am able to do it with normal for loop but i want to use only list comprehension

You can use:

In [20]: [k for e in a for k in (e if isinstance(e, list) else [e])]...: 
Out[20]: [2, 33, 4, 2, 3, 4, 6]