what is a child inheritance in python with example

1# =============================================================================
2# Inhertance
3# =============================================================================
4class A:
5    def feature1(self):
6        print('Feature 1 in process...')
7    def feature2(self):
8        print('Feature 2 in process...')       #Pt.1
9        
10class B:
11    def feature3(self):
12        print('Feature 3 in process...')
13    def feature4(self):
14        print ('Feature 4 in process...')
15        
16a1 = A() 
17
18a1.feature1()
19a1.feature2()
20
21a2 = B()
22
23a2.feature3()
24a2.feature4()
25# THE ABOVE PROGRAM IS A PROGRAM WITHOUT USING INHERITANCE
26        
27# WITH THE USE OF INHERITANCE IS BELOW
28class A:
29    def feature1(self):
30        print('Feature 1 in process...')    
31    def feature2(self):
32        print('Feature 2 in process...')
33        
34class B(A):
35    def feature3(self):
36        print('Feature 3 in process...')    # Pt.2
37    def feature4(self):
38        print ('Feature 4 in process...')
39        
40a1 = A() 
41
42a1.feature1()
43a1.feature2()
44
45a2 = B()
46
47a2.feature3()
48a2.feature4()
49
50
51# NOW TO CHECK OUT THE DIFFERENCE BETWEEN Pt.1
52# AND Pt.2 TRY RUNNIG THE CODE ON THE BASIS OF
53# INHERITANCE, IN OTHER WORDS TRY RUNNING ONLY 
54# B CLASS IN Pt.2 AND THEN RUN ONLY a2
55# YOU WILL SEE A DIFFERENCE IN THE RUNNING OF 
56# ONLY a2,,,, IT WILL STILL SHOW THAT FEATURE 3
57# AND 4 IS IN PROCESS,, THIS MEANS THAT B IS THE