You are confused.
This
['a','b','c','d']
is already a python list
This
('a','b','c','d')
is a python tuple
To convert from a list to a tuple, try this:
#This is a list
python_list=['a','b','c','d']
print(python_list)
python_tuple = tuple(python_list)
#This is a tuple
print(python_tuple)
and you get
['a', 'b', 'c', 'd']
('a', 'b', 'c', 'd')
In fact, to convert to and forth between list and tuple, use
list(python_tuple)
and
tuple(python_list)
respectively.