stopiteration error in python code example

Example: stopiteration error python

# When an iterator is done, it’s next method raises StopIteration. This exception is 
# not considered an error. We re-write the given code as follows to catch the 
# exception and know its type.

Example
import sys
try:
z = [5, 9, 7]
i = iter(z)
print i
print i.next()
print i.next()
print i.next()
print i.next()
except Exception as e:
print e
print sys.exc_type
Output
<listiterator object at 0x0000000002AF23C8>
5
9
7
<type 'exceptions.StopIteration'>