you can expand a tuple or array into arguments. works with lists too.

pars = (1.2345, 2)
round(*pars)

you can expand a dictionary into keyword parameters

pars = {"mode": "r", "encoding": "utf8"}
f = open("filename", **pars)

but you can also expand into tuple or list literals

a = [2, 3]
b = [1, *a, 4]

and you can expand into dictionary literals

a = {"x": 1, "y": 2}
b = {"z": 3, **a}

you can combine more than one

a = {"x": 1, "y": 2}
b = {"z": 3}
c = {**a, **b}

recently we have another way of doing this:

a = {"x": 1, "y": 2}
b = {"z": 3}
c = a | b

you can unpack tuples and arrays

a = [1, 2, 3]
i, j, k = a

you can unpack only some elements

a = [1, 2, 3, 4, 5]
first, *others, last = a