More than one argument


Little confused as to what to do. Its telling me to add the parameters together..not sure what that means exactly
m = 5
n = 13
def add_function(x,y):

print add_function(m, n)


Parameters is just fancy talk for plain items, so to add parameters together in the function you would put:

return x + y


i have a doubt that can we write program like this

def add_function(x, y):
z = x + y
return z
when i wrote this program it told me 'z' is not defined. could any one tell me whey it tell's like that?
And i have another doubt, why we have to write

print def_function(m, n)

could you clarify my doubt.