Python AttributeError when referencing a settings class

Question

I'm attempting to import a class called "Settings" into a pygame code.

The calling code

import sys # used to exit game when user is done

import pygame

from settings import Settings

def run_game():
    #initialize game and create screen object
    pygame.init()
    ai_settings = Settings()

    screen =pygame.display.set_mode((1200, 800))

The settings.py file

#settings for alien_invasion
class Settings():
    """A class to store all settings for Alien Invasion"""

    def _init_(self):
        #intialize games settings
        self.screen_width=1200
        self.screen_height=800
        self.bg_color=(230,230,230)

I'm aware that this is likely a syntax error, but I've searched around and can't quite find what I'm doing wrong.

The exact error that I'm getting is

AttributeError: 'Settings' object has no attribute 'screen_width'