Write a function birthday that prints a birthday message. Determine by yourself which parameters should be given to the function, in order for it to be used as illustrated in the interactive Python session below.

>>> birthday.__doc__
'Shows a message with the name and age of the birthday boy/girl.'
>>> birthday()
'Happy birthday Lena! I hear that you turned 2 today.'
>>> birthday('Marte')
'Happy birthday Marte! I hear that you turned 2 today.'
>>> birthday('Cas', 4)
'Happy birthday Cas! I hear that you turned 4 today.'
>>> birthday('Nom', age=2)
'Happy birthday Nom! I hear that you turned 2 today.'
>>> birthday(age=3, name='Lauren')
'Happy birthday Lauren! I hear that you turned 3 today.'