[Tutor] How arguments to the super() function works?

[Arup Rakshit]

> On 19-May-2019, at 4:46 AM, Mark Lawrence <breamoreboy at gmail.com> wrote:
> 
> On 18/05/2019 17:21, Arup Rakshit wrote:
>> I am writing an Flask app following a book, where a piece of python concept I am not getting how it works. Code is:
>> class Role(db.Model):
>>     __tablename__ = 'roles'
>>     id = db.Column(db.Integer, primary_key=True)
>>     name = db.Column(db.String(64), unique=True)
>>     default = db.Column(db.Boolean, default=False, index=True)
>>     permissions = db.Column(db.Integer)
>>     users = db.relationship('User', backref='role', lazy='dynamic')
>>     def __init__(self, **kwargs):
>>         super(Role, self).__init__(**kwargs)
>>         if self.permissions is None:
>>             self.permissions = 0
>> Here, why super(Role, self).__init__(**kwargs) is used instead of super().__init__(**kwargs) ? What that Role and self argument is instructing the super() ?
>> Thanks,
>> Arup Rakshit
>> ar at zeit.io
> 
> Please check this https://www.youtube.com/watch?v=EiOglTERPEo out.  If that doesn't answer your question please ask again.
> 


Hello Mark,

Thanks for sharing the link. Just finished the talk. Little better now about how super uses the MRO.

class Dad:
    def can_i_take_your_car(self):
        print("No...")

class Mom(Dad):
    def can_i_take_your_car(self):
        print("Asking your dad...")

class Victor(Mom, Dad):
    def can_i_take_your_car(self):
        print("Asking mom...")

class Pinki(Mom, Dad):
    def can_i_take_your_car(self):
        print("I need it today..")

class Debu(Pinki, Victor):
    def can_i_take_your_car(self):
        super(Victor, self).can_i_take_your_car()

In this piece of code:

print(Debu().can_i_take_your_car())

Why the above call prints "Asking your dad…” but not " print("Asking mom…”)” although can_i_take_your_car is defined inside the class Victor ?

help(Debu) #prints

Help on class Debu in module __main__:

class Debu(Pinki, Victor)
 |  Method resolution order:
 |      Debu
 |      Pinki
 |      Victor
 |      Mom
 |      Dad
 |      builtins.object
 |  
 |  Methods defined here:
 |  
 |  can_i_take_your_car(self)
 |  
 |  ----------------------------------------------------------------------
 |  Data descriptors inherited from Dad:
 |  
 |  __dict__
 |      dictionary for instance variables (if defined)
 |  
 |  __weakref__
 |      list of weak references to the object (if defined)


Last question: Why duplicate PEPs for the same thing https://www.python.org/dev/peps/pep-0367/ and https://www.python.org/dev/peps/pep-3135/#specification ? Which one to read when such duplicate exists?

> -- 
> My fellow Pythonistas, ask not what our language can do for you, ask
> what you can do for our language.
> 
> Mark Lawrence
> 
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Thanks,

Arup Rakshit
ar at zeit.io