this is needed to translate the messages using _() in validators

    """

    _ = staticmethod(_)

def M(self, key, state=None, **kwargs):

    """

    returns string from self.message based on given key,

    passed kw params are used to substitute %(named)s params inside

    translated strings

    :param msg:

    :param state:

    """

    if state is None:

        state = StateObj()

    else:

        state._ = staticmethod(_)

    #inject validator into state object

    return self.message(key, state, **kwargs)

def ValidUsername(edit=False, old_data={}):

    class _validator(formencode.validators.FancyValidator):

        messages = {

            'username_exists': _(u'Username "%(username)s" already exists'),

            'system_invalid_username':

                _(u'Username "%(username)s" is forbidden'),

            'invalid_username':

                _(u'Username may only contain alphanumeric characters '

                  'underscores, periods or dashes and must begin with '

                  'alphanumeric character')

        }

        def validate_python(self, value, state):

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

                msg = M(self, 'system_invalid_username', state, username=value)

                raise formencode.Invalid(msg, value, state)

            #check if user is unique

            old_un = None

            if edit:

                old_un = User.get(old_data.get('user_id')).username

            if old_un != value or not edit:

                if User.get_by_username(value, case_insensitive=True):

                    msg = M(self, 'username_exists', state, username=value)

                    raise formencode.Invalid(msg, value, state)

                msg = M(self, 'invalid_username', state)

                raise formencode.Invalid(msg, value, state)

    return _validator

def ValidRepoUser():

    class _validator(formencode.validators.FancyValidator):

        messages = {

            'invalid_username': _(u'Username %(username)s is not valid')

        }

        def validate_python(self, value, state):

            try:

                User.query().filter(User.active == True)\

                    .filter(User.username == value).one()

            except Exception:

                msg = M(self, 'invalid_username', state, username=value)

                raise formencode.Invalid(msg, value, state,

                    error_dict=dict(username=msg)

                )

    return _validator

def ValidUsersGroup(edit=False, old_data={}):

    class _validator(formencode.validators.FancyValidator):

        messages = {

            'invalid_group': _(u'Invalid users group name'),

            'group_exist': _(u'Users group "%(usersgroup)s" already exists'),

            'invalid_usersgroup_name':

                _(u'users group name may only contain  alphanumeric '

                  'characters underscores, periods or dashes and must begin '

                  'with alphanumeric character')

        }

        def validate_python(self, value, state):

            if value in ['default']:

                msg = M(self, 'invalid_group', state)

                raise formencode.Invalid(msg, value, state,

                    error_dict=dict(users_group_name=msg)

                )

            #check if group is unique

            old_ugname = None

            if edit:

                old_id = old_data.get('users_group_id')

                old_ugname = UsersGroup.get(old_id).users_group_name

            if old_ugname != value or not edit: