Question: I have a class where I would like to instantiate the object in several ways depending on the arguments. When I pass a filepath to the function `__init__` it should restore all parameters from the object saved as a pickle file. Is there any smart way to do so, something like `self=load(...)`

Answer: 
Doing `self=load(...)` in your `__init__` only masks the local `self` variable in the `__init__`, it does not change the instance.

You can instead control the creation of the new instance in the [`__new__`](https://docs.python.org/2/reference/datamodel.html#object.__new__) method of the class. 

```
import pickle

class Pretty(object):
    def __new__(cls, filepath=None, *args, **kwargs):
        if filepath:
            with open(filepath) as f:
               inst = pickle.load(f)
            if not isinstance(inst, cls):
               raise TypeError('Unpickled object is not of type {}'.format(cls))
        else:
            inst = super(Pretty, cls).__new__(cls, *args, **kwargs)
        return inst

```

You can do a quick instance check of the unpickled object to ensure it is actually an instance of your class, otherwise you can expect bad behavior such as the `__init__` method of your class not being called.
As stated in another answer, `self = load(...)` only replaces the local variable `self`. The same answer recommends resorting to the `__new__` method of the class which works but isn't a good practice in python, as overriding this method should be used for immutable types only.

Instead, you should be using a [factory](https://en.wikipedia.org/wiki/Factory_(object-oriented_programming)), which can in this case be a simple function :

```
def foo_factory(filename=None, *args, **kwargs):
    if filename:
        foo_factory.foo = pickle.load(filename)
    else:
        foo_factory.foo = Foo(*args, **kwargs)
    return foo_factory.foo

```

where we supposed that class `Foo` is the class of interest.

(see [Why is \_\_init\_\_() always called after \_\_new\_\_()?](https://stackoverflow.com/questions/674304/why-is-init-always-called-after-new) for more details and references)