designing my ticket api

I have a function named getTicket which take two argument id which is a number and format (string)

def getTicket(id, format):
    if format == "pdf":
        getTicketPDF(id) #some specialized pdf method gets called
    elif format == "json":
        getTicketJSON(id) #specialized json method

Now if I have to support some new format like "html" then I can create another elif for html.

But I want to generalize this code so that if in future n new method gets added I do not have to change my code

How can I design my getTicket api?