Conversion of List of Tuples

[subhabangalore at gmail.com]

Dear Group,

I have a tuple of list as,

tup_list=[(1,2), (3,4)]
Now if I want to covert as a simple list,

list=[1,2,3,4]

how may I do that?

If any one can kindly suggest? Googling didn't help much.

Regards,
Subhabrata.