Decorator is using in class,but not working

[mbilalshafiq]

# -*- coding: utf-8 -*-
"""
Created on Mon Jun 22 23:46:47 2020

@author: Lenovo
"""
import pdb
import unittest
import math

class Calculator:
    """
    A class is defined for calculator, to preform addition,subtration,multiplication,divison,power and exponent.
    """
    def __init__(self,num1,num2):
        try:
            assert type(num1) == int
            assert type(num2) == int
        except AssertionError:
            print('Invalid parameter type')
            raise Exception
        
        self.num1 = num1
        self.num2 = num2
        
        
    def addition(self):
        #pdb.set_trace()# we have added a breakpoint here. The code pause execution here.
        #print(' Addition')
        return (self.num1 + self.num2)
    def subtraction(self):
        return(self.num1 - self.num2)
    
    def division(self):
        return(self.num1 / self.num2)
    
    def moduler(self):
        return(self.num1 // self.num2)      
  
    def multiplication(self):
        return(self.num1 * self.num2)
        
    """def power(self):
        return(self.num1 ** self.num2)
       """ 
class ScientificCalculator(Calculator): #parent class refrence Calculator
    def __init__(self,num1,num2): #should be initialize this function __init__()
        super().__init__(num1,num2) # super() will refer paranent class variables
        self.num1 = num1
        self.num2 = num2

    def logg(self):
        #pdb.set_trace()  #we have added a breakpoint here. The code pause execution here.
        return math.log(self.num1,self.num2)

    def power(self):
        return (lambda a,b:a**b)(self.num1,self.num2)
    
    def extract_function_name(func):
        def internal_method(*args,**kwargs):
            print('the method called is:',func.__name__)
            returned_value = func(*args,**kwargs)
            print('the method execution is complete')
            return returned_value
    
    #adding decorator to the function
    @extract_function_name
    def factorial(self):
        #return (lambda a:a) ([self.num1 if self.num1 == 0 self.num1 = 1 else self.num1 * factorial(self.num1 - 1)])
        return (lambda a:a) (math.factorial(self.num1))

cal= Calculator(num1 = 2,num2 = 2)
print('addition',cal.addition())
print('subtraction',cal.subtraction())
print('division',cal.division())
print('multiplication',cal.multiplication())
print('moduler',cal.moduler())
sci_cal = ScientificCalculator(4,3)
print('log:',sci_cal.logg())
print('power:',sci_cal.power())
print('factorial:',sci_cal.factorial())

Error:
PythonBetaTheNextLevelUpPart3_Decorator_Lambda_Ex2.py", line 81, in <module>
    print('factorial:',sci_cal.factorial())

TypeError: 'NoneType' object is not callable

[Yoriz]

Your decorator extract_function_name does not need to be in class ScientificCalculator
and it needs to return internal_method, at the moment it defaults to returning None.

def extract_function_name(func):
    def internal_method(*args,**kwargs):
        print('the method called is:',func.__name__)
        returned_value = func(*args,**kwargs)
        print('the method execution is complete')
        return returned_value
    return internal_method 

[mbilalshafiq]

Your decorator extract_function_name does not need to be in class ScientificCalculator
and it needs to return internal_method, at the moment it defaults to returning None.

def extract_function_name(func):
    def internal_method(*args,**kwargs):
        print('the method called is:',func.__name__)
        returned_value = func(*args,**kwargs)
        print('the method execution is complete')
        return returned_value
    return internal_method 

Now is working , thanks your guidance.