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Starred expression
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``*args`` and ``**kwargs`` are legendary name for iterable and dict. 

**Example: Uncertain arguments:**

.. code:: python

  def foo(*args, **kwargs):
      print(args)
      print(kwargs)

  >>> foo(1, 2, "abc", a = 1, b = 2, c = 3)

**Example: Unpacking inputs:**

.. code:: python

  def foo(num, a):
      print(num)
      print(a)

  t = (3,)
  d = {'a': 1}
  >>> foo(*t, **d)

Here inside foo, ``args`` is a tuple and ``kwargs`` is a dict.
Here when you use a starred expression in a function call, t has to be a iterable and d has to be a dictionary.

.. _construct-iterable:

**Example: Construct iterable:**

.. code:: python

  >>> *ls, = range(5)
  >>> ls
  [0, 1, 2, 3, 4]

.. caution::

  The comma ``,`` after ``ls`` is necessary.

**Example: Extract from iterable:**

.. code:: python

  *(a, *b), c = 'this'

This is kind of tricky to find out which is which. It's clear ``c = 's'``.
Then ``a, *b = "thi"``. Then ``a = 't'`` and ``*b`` is ``"hi"``. So ``b = ['h', 'i']``.