stuck please assist

import datetime

from peewee import *

from argon2 import PasswordHasher

DATABASE = SqliteDatabase('recipes.db')
HASHER = PasswordHasher()

class User(Model):
    username = CharField(unique=True)
    password = CharField()

    class Meta:
        database = DATABASE

    @classmethod
    def create_user(cls, username, password):
        try:
            cls.get(cls.username**username)
        except cls.DoesNotExist:
            user = cls(username=username)
            # TODO: hash user password here?
            user.save()
            return user
        else:
            raise Exception("User already exists")        

    @staticmethod   
    def hash_password(password):
        return HASHER.hash(password)


class Recipe(Model):
    name = CharField()
    created_at = DateTimeField(default=datetime.datetime.now)

    class Meta:
        database = DATABASE


class Ingredient(Model):
    name = CharField()
    description = CharField()
    quantity = DecimalField()
    measurement_type = CharField()
    recipe = ForeignKeyField(Recipe)

    class Meta:
        database = DATABASE


def initialize():
    DATABASE.connect()
    DATABASE.create_tables([User, Recipe, Ingredient], safe=True)
    DATABASE.close()