What is displayed after running the following?

def uc$($letter$)$:

if letter $==\text{'}h\text{'}$:

return $\text{'}H\text{'}$

else:

return letter

print$($uc$(\text{'}$a$\text{'}),$ uc$(\text{'}$h$\text{'}))$

a H

Ah

$AH$

ah