How to handle the "else" when converting an if..elif..else into a dictionary lookup?

I am trying to remove if else from python. One option is to convert it into dictionary. But now problem is for last else part.

val=3

if val==1:
  print "a"
elif val==2:
  print "b"
elif val==3:
  print "c"
elif val==4:
  print "d"
else:
  print "value not found:"

print "===========Converted if else into dictionary ==================="

DATA_SOURCE = {1:"a",2:"b",3:"c",4:"d"}
print DATA_SOURCE[val]

I have found below option. Can someone suggest whether it is correct .

if not DATA_SOURCE.has_key(val):
  print "value not found:"
else:
  print DATA_SOURCE[val]

I have seen setdefault option somewhere but could not understand. Please someone suggest me proper option.