patching nested objects in python

A better design would be to pass the necessary clients as arguments, rather than make each class responsible for knowing how to instantiate such a client.

import os


class PasswordClient:
    def __init__(self, value):
        self.password_db = value

class DBClient:
    def __init__(self, pc):
        self.password_client = pc


class TableQuery:
    def __init__(self, dbc):
        self.db_client = dbc

    def add_person(self):
        ...



a = TableQuery(DBClient(PasswordClient(...)))
a.add_person()