I was dealing exactly the same question and actually ended up with the same solution as kecer suggested. Since I need to use it in dozens of scripts, I've created own library. Let me share this solution with you.

credlib.py -- universal library to handle credentials

class credential:
    def __init__(self, hostname, username, password):
        self.hostname = hostname
        self.username = username
        self.password = password

mycredentials.py -- my local file to store all credentials

from credlib import credential
sys_prod = credential("srv01", "user", "pass")
sys_stg = credential("srv02", "user", "pass")
sys_db = credential("db01", "userdb", "passdb")

mysystemlib.py -- this is a general library to access my system (both new credential system and legacy is supported)

from credlib import credential

def system_login(*args): # this is new function definition
#def system_login(hostname, username, password): # this was previous function definition

    if len(args) == 1 and isinstance(args[0], credential):
        hostname = args[0].hostname
        username = args[0].username
        password = args[0].password
    elif len(args) == 3:
        hostname = args[0]
        username = args[1]
        password = args[2]
    else:
        raise ValueError('Invalid arguments')

    do_login(hostname, username, password) # this is original system login call

main.py -- main script that combines credentials and system libs

from mycredentials import sys_stg, sys_db
import mysystemlib
...
mysystemlib.system_login(sys_stg)

Please note that the legacy hostname/username/password way still works so it does not affect old scripts:

mysystemlib.system_login("srv02", "user", "pass")

This has a lot benefits:

• same credential system across all our python scripts
• files with passwords are separated (files can have more strict permissions)
• files are not stored in our git repositories (excluded via .gitignore) so that our python scripts/libs can be shared with others without exposing credentials (everyone defines their own credentials in their local files)
• if a password needs to be changed, we do it at a single place only