extra empty element when removing an element from a tuple

Question

I have a question about the following python outcome. Suppose I have a tuple :

a = ( (1,1), (2,2), (3,3) )

I want to remove (2,2)

Answer 1

Python uses a trailing comma in case a tuple has only one element:

In [21]: type((1,))
Out[21]: tuple

from the docs:

A special problem is the construction of tuples containing 0 or 1 items: the syntax has some extra quirks to accommodate these. Empty tuples are constructed by an empty pair of parentheses; a tuple with one item is constructed by following a value with a comma (it is not sufficient to enclose a single value in parentheses).

>>> empty = ()
>>> singleton = 'hello',    # <-- note trailing comma
>>> len(empty)
0
>>> len(singleton)
1
>>> singleton
('hello',)