Use key_name instead of link_id
Some entities do not have a link_id, but all entities are guaranteed
to have a key_name (or an id).
"""
The md5 and sha modules are deprecated since Python 2.5, replaced by the
hashlib module containing both hash algorithms. Here, we provide a common
interface to the md5 and sha constructors, preferring the hashlib module when
available.
"""
try:
import hashlib
md5_constructor = hashlib.md5
sha_constructor = hashlib.sha1
except ImportError:
import md5
md5_constructor = md5.new
import sha
sha_constructor = sha.new