Solution to coding challenge 6

#writing data to the file 
f= open('demo.txt', 'w')
f.write("hello there")
f.close() 
#reading data from the file 
f= open('demo.txt','r')
print(f.read())
f.close() 
#adding additional contents 
f= open('demo.txt','a')
f.write('\n Hello again')
f.close()