while 1:
    try:
        line = raw_input()     # read from stdin
    except EOFError:
        break
    else:
        <process 'next' here>

###

Found = "Item found"

def searcher():
    <raise Found or return>

try:
    searcher()
except Found:
    <success>
else:
    <failure>

###

try:
    <run program>        
except:              # all uncaught exceptions come here
    import sys
    print 'uncaught!', sys.exc_info()[0], sys.exc_info()[1]