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Update (September 2020)

@PPC: your dream has come true.

Since Python 3.7, a new tool is available as a standard: dataclasses (unsurprisingly, the designer of the named list package, Eric V. Smith, is also behind it).

In essence, it provides an automatic initialization of class variables.

from dataclasses import dataclass

@dataclass
class InventoryItem:
    """Class for keeping track of an item in inventory."""
    name: str
    unit_price: float
    quantity_on_hand: int = 0

    def total_cost(self) -> float:
        return self.unit_price * self.quantity_on_hand

(from the official doc)

What the @dataclass decorator will do, will be to automatically add the __init__() method:

def __init__(self, name: str, unit_price: float, quantity_on_hand: int=0):
    self.name = name
    self.unit_price = unit_price
    self.quantity_on_hand = quantity_on_hand

IMHO, it's a pretty, eminently pythonic solution.

Eric also maintains a backport of dataclasses on github, for Python 3.6.

Let's say its the "quick and dirty way", which could work in a number of cases. In general there is not even the need to declare your class.

But what if you want that instance to be mutable, i.e. update the elements of the instance? The answer is the named list (also known as RecordClass). Conceptually a list where the items are accessible with the dot notation.

If you use them well, this might significant cut down time spent on writing classes and handling instances!

Let's say its the "quick and dirty way", which would work in a number of cases. In general there is not even the need to declare your class.

But what if you want that instance to be mutable, i.e. to allow you update the properties of the instance? The answer is the named list (also known as RecordClass). Conceptually it is like a normal list, where the items are also accessible with the dot notation.

If you use them well, this might significantly cut down time spent on writing classes and handling instances!

instance.var1 = var1
instance.var2 = var2

instance = AClass(var1, var2)

instance = AClass(var1, var2)

instance = SimpleNamespace()
instance.var1 = var1
instance.var2 = var2

instance = AClass(var1, var2)

or

instance = AClass(var1=var1, var2=var2)

instance = AClass(var1, var2)

or:

instance = AClass(var1=var1, var2=var2)

And you can then modify them:

instance.var1 = var3

But you can't add an attribute that is not defined.

>>> instance.var4 = var4
  File "<stdin>", line 1, in <module>
AttributeError: 'instance' object has no attribute 'var4'