From tuple to list to tuple :
a = ('2',)
b = 'b'
l = list(a)
l.append(b)
tuple(l)
Or with a longer list of items to append
a = ('2',)
items = ['o', 'k', 'd', 'o']
l = list(a)
for x in items:
l.append(x)
print tuple(l)
gives you
>>>
('2', 'o', 'k', 'd', 'o')
The point here is: List is a mutable sequence type. So you can change a given list by adding or removing elements. Tuple is an immutable sequence type. You can't change a tuple. So you have to create a new one.