def hello_3(greeting='Hello', name='world'):
print '%s, %s!' % (greeting, name)
hello_3()
hello_3('Greetings')
hello_3('Greetings', 'universe')
hello_3(name='Gumby')
def hello_4(name, greeting='Hello', punctuation='!'):
print '%s, %s%s' % (greeting, name, punctuation)
hello_4('Mars')
hello_4('Mars', 'Hi')
hello_4('Mars', 'Hi', '...')
hello_4('Mars', punctuation='.')
hello_4('Mars', greeting='It is a greeting!')