Best form of iterating over a lsit of lists

[snippsat]

When you loop for name, species, weight in pets:  is equivalent to name, species, weight = pets[0] loop name, species, weight = pets[1] loop ...ect.
So you are unpacking values to a tuple name, species, weight.
Why is it a tuple?

>>> pets = [["Garfield", "cat", 4],
...         ["Dog", "dog", 7.5],
...         ["Porkey", "pig", 61],
...         ["Stoned", "rock", 0.230] ]

>>> name, species, weight = pets[0]
>>> name, species, weight
('Garfield', 'cat', 4)

>>> # Or to make it clear
>>> 'a', 'b', 'c'
('a', 'b', 'c')

>>> name
'Garfield'
>>> species
'cat'
>>> weight
4

So can use () or [],but it's not needed and in a loop is just confusing.
Outside of loop it can be used to make clear that it's a tuple.

>>> tup  = 1, 'a'
>>> tup
(1, 'a')

>>> tup1 = (1, 'a')
>>> tup1
(1, 'a')

>>> tup == tup1
True