def add(self, hostname, keytype, key):
for e in self._entries:<EOL><INDENT>if (hostname in e.hostnames) and (e.key.get_name() == keytype):<EOL><INDENT>e.key = key<EOL>return<EOL><DEDENT><DEDENT>self._entries.append(HostKeyEntry([hostname], key))<EOL>
Add a host key entry to the table.  Any existing entry for a
C{(hostname, keytype)} pair will be replaced.

@param hostname: the hostname (or IP) to add
@type hostname: str
@param keytype: key type (C{"ssh-rsa"} or C{"ssh-dss"})
@type keytype: str
@param key: the key to add
@type key: L{PKey}