How do I find out what Exceptions a class may raise

at Been using the ActionMailer class, i.e.

class SimpleMailer < ActionMailer::Base
def simple_message(to,sender,subject_line,message)
from sender
recipients to
subject subject_line
body message

But what I cant work out is what exceptions it can raise. Had a look
at its documentation at
ActionMailer::Base but it does
not mention exceptions.

Ime fairly new to this and I guess my question is a general one on how
do you find out the exceptions a class can raise?