Adding methods to GAE database class - google-app-engine

Question

I am messing around with GAE. I want to place my database object in one file and call it from another. Here is the DB object:
import webapp2
import os
import jinja2
import json
import logging
import main
from google.appengine.ext import db
class User(db.Model):
user_name = db.StringProperty(required = True)
hashed_password = db.StringProperty(required = True)
email = db.EmailProperty(required = True)
created_dttm = db.DateTimeProperty(auto_now_add = True)
last_modified = db.DateTimeProperty(auto_now = True)
coords = db.GeoPtProperty(required = False)
# def as_dict(self):
# time_fmt = '%c'
# d = {
# 'subject':self.subject,
# 'content':self.content,
# 'created':self.created_dttm.strftime(time_fmt),
# 'last_modified': self.last_modified.strftime(time_fmt)
# }
# return d
def isValueUnique(self,column,value):
result = None
q = User.all()
q.filter(column, value)
result = q.get()
return result
I cannot instantiate the DB because it thinks I'm trying to store data.
I want to call the isValueUnique method from another file like so:
import webapp2
import os
import jinja2
import json
import logging
import main
import database
import validation
from google.appengine.ext import db
class SignUp(main.Handler):
def post(self):
user_username = self.request.get("username")
user_email = self.request.get("email")
user_pass = self.request.get("password")
user_verify = self.request.get("verify")
valid = validation.Valid()
error1=""
error2=""
error3=""
error4=""
q = database.User.all()
q.filter("username =", user_username)
result = q.get()
if result:
error1="Username already taken"
if (not valid.valid_user(user_username)) and (not error1):
error1 = "Enter a valid username"
if not valid.valid_password(user_pass):
error2 = "Enter a valid password"
if not valid.valid_pass_match(user_pass,user_verify):
error3 = "Passwords must match"
# Email Validation
email=valid.valid_email(user_email)
if not email:
error4 = "Invalid email"
email=""
elif not database.User.isValueUnique("email",email):
error4 = "Email already in use, please sign in"
email=""
I get this error:
elif not database.User.isValueUnique("email",email):
TypeError: unbound method isValueUnique() must be called with User instance as first argument (got str instance instead)
I can't instantiate User like I already said. What is the work around here?

Answer 1

database.User.isValueUnique("email",email)
This is attempting to call a method on the database.User class, but isValueUnique is an instance method.
If you decorate isValueUnique with #staticmethod you'll get farther.
Where are you trying to instantiate a User?