# Exercise 3.20

# Define functions

def hw1():
    return 'Hello, World!'

def hw2():
    print 'Hello, World!'
    
def hw3(x,y):               # First implementation
    return '%s%s' % (x,y)
  
def hw3(x,y):               # Second implementation
    return x+y

# Test functions
print hw1()

hw2()

print hw3('Hello, ', 'World!')

print hw3('Python ', 'function')