in case the credentials should be loaded from an external file

My particular use case is that I want to version control the .cfg
file, but I don't want to put my username/password in the file

Mostly in regards to unicode string handling.

Ldap search results returns "keys" in utf-8, but values are often in
bytes. stringify values after querying so that results and cache
aren't treated differently.

Open files in text mode instead of binary mode.

SafeConfigParser was renamed to ConfigParser in python3.

LOG.warn is deprecated, change to "LOG.warning" to avoid deprecation
output messages.

... such as pass from the passwordstore

See #1 (comment)

allow setting password by passing command