if value != authentication_token():

            raise formencode.Invalid(self.message('invalid_token', state,

                                            search_number=value), value, state)

class ValidUsername(formencode.validators.FancyValidator):

    def validate_python(self, value, state):

        if value in ['default', 'new_user']:

            raise formencode.Invalid(_('Invalid username'), value, state)

class ValidPassword(formencode.validators.FancyValidator):

    def to_python(self, value, state):

class ValidAuth(formencode.validators.FancyValidator):

    messages = {

            'invalid_password':_('invalid password'),

            'invalid_login':_('invalid user name'),

            'disabled_account':_('Your acccount is disabled')

            }

    #error mapping

    e_dict = {'username':messages['invalid_login'],

              'password':messages['invalid_password']}

    e_dict_disable = {'username':messages['disabled_account']}

            self.sa.rollback()

            raise      

    def update(self, id, form_data):

        try:

            new_user = self.sa.query(User).get(id)

            if new_user.username == 'default':

                raise DefaultUserException(

                                _("You can't Edit this user since it's" 

                                  " crucial for entire application"))

            for k, v in form_data.items():

                if k == 'new_password' and v != '':

                    new_user.password = v

                else:

                    setattr(new_user, k, v)

            self.sa.add(new_user)

            self.sa.commit()

        except Exception as e:

            log.error(e)

            self.sa.rollback()

            raise      

    def delete(self, id):