I am assuming that you have a 53 items list and if so, the final item needs the thelist[52] tag due to the reason of the indexing starting at 0. An IndexError is brought into account once the user tries to retrieve the index from a given sequence such as a tuple wherein, the index is not found in that sequence. The exception for this in Python is raised when the subscript of the sequence is out of the range. Refer to the example below that gets the IndexError:-
test = list(range(53))
test[53]
IndexError Traceback (most recent call last)
<ipython-input-6-7879607f7f36> in <module>
1 test = list(range(53))
----> 2 test[53]
IndexError: list index out of range