缺少1个必需的位置参数：'self'缺失

Question

I have found a couple of Stackoverflow posts where people have had the same issue but cannot seem to implement the suggested fixes in a satisfactory mannor for python to compile my script.

I understand that it wants self to be passed into database but cannot understand where I am going to get this from as self from my main.py contains the wrong context.

I have my main class in which I want to call the database class and execute a function from within.

main.py

class Main:
    def __init__(self):
        self.db = Database
        self.db.createConnection()

database.py

class Database:
    def __init__(self):
            #some setup here

    def createConnection(self):
            #Create connection code here

When I run this, I am presented with the following error.

TypeError: createConnection() missing 1 required positional argument: 'self'

Answer 1

You want to assign an instance of Database to self.db , not assign the Database class itself. Add parentheses to call Database and instantiate it:

self.db = Database()