new file:   ex10.py
	new file:   ex11.py
	new file:   ex12.py
	new file:   ex13.py
	new file:   ex14.py
	new file:   ex15.py
	new file:   ex15_sample.txt
	new file:   ex16.py
	new file:   ex17.py
	new file:   ex9.py
	new file:   test.txt
	new file:   test17.txt