'Finds user by username or email'

def find_user(self, username=None, email=None):

    if username:
        return self.get_session.query(self.user_model).filter((func.lower(self.user_model.username) == func.lower(username))).first()
    elif email:
        return self.get_session.query(self.user_model).filter_by(email=email).first()
