How to use the taguette.validate.InvalidFormat function in taguette

raise HTTPError(404)
        if not self.application.config['REGISTRATION_ENABLED']:
            raise HTTPError(403)
        try:
            login = self.get_body_argument('login')
            password1 = self.get_body_argument('password1')
            password2 = self.get_body_argument('password2')
            login = validate.user_login(login)
            validate.user_password(password1)
            email = self.get_body_argument('email', '')
            if email:
                validate.user_email(email)
            if password1 != password2:
                raise validate.InvalidFormat(_f("Passwords do not match"))
            if self.db.query(database.User).get(login) is not None:
                raise validate.InvalidFormat(_f("User name is taken"))
            if (email and
                    self.db.query(database.User)
                    .filter(database.User.email == email).count() > 0):
                raise validate.InvalidFormat(_f("Email address is already "
                                                "used"))
            user = database.User(login=login)
            user.set_password(password1)
            if email:
                user.email = email
            self.db.add(user)
            self.db.commit()
            logger.info("User registered: %r", login)
            self.set_secure_cookie('user', login)
            return self.redirect(self.reverse_url('index'))
        except validate.InvalidFormat as e:
            logger.info("Error validating Register: %r", e)

if not self.application.config['MULTIUSER']:
            raise HTTPError(404)
        reset_token = self.get_body_argument('reset_token')
        try:
            user = self.decode_reset_token(reset_token)
        except HTTPError as e:
            self.set_status(403)
            return self.finish(
                self.gettext(e.log_message),
            )
        try:
            password1 = self.get_body_argument('password1')
            password2 = self.get_body_argument('password2')
            validate.user_password(password1)
            if password1 != password2:
                raise validate.InvalidFormat(_f("Passwords do not match"))
            logger.info("Password reset: changing password for %r", user.login)
            user.set_password(password1)
            self.db.commit()
            return self.redirect(self.reverse_url('index'))
        except validate.InvalidFormat as e:
            logger.info("Error validating SetNewPassword: %r", e)
            return self.render('new_password.html', reset_token=reset_token,
                               error=self.gettext(e.message))

# Should update via the cascade:
    # op.execute('UPDATE project_members SET user_login = lower(user_login);')
    # op.execute('UPDATE commands SET user_login = lower(user_login);')

    # Check that logins pass new validation requirements
    bind = op.get_bind()
    session = Session(bind=bind)
    logins = session.execute('''\
        SELECT login FROM users;
    ''')
    error = False
    for row in logins:
        login, = row
        try:
            changed = validate.user_login(login)
        except validate.InvalidFormat:
            error = True
            print("User login %r does not abide to new restrictions" % login,
                  file=sys.stderr)
        else:
            if changed != login:
                raise ValueError("Login %r is still not canonical after "
                                 "migration, please report this bug!" % login)
    if error:
        raise ValueError("Some user logins do not pass validation")
    session.close()

def post(self):
        if not self.application.config['MULTIUSER']:
            raise HTTPError(404)
        login = self.get_json()['login']
        try:
            login = validate.user_login(login)
        except validate.InvalidFormat:
            pass
        else:
            user = self.db.query(database.User).get(login)
            if user is not None:
                return self.send_json({'exists': True})
        return self.send_json({'exists': False})

def user_login(login):
    if not login:
        raise InvalidFormat(_f("User login cannot be empty"))
    if len(login) > 20:
        raise InvalidFormat(_f("User login is too long"))
    login = login.lower()
    if any(c not in ALLOWED_LOGIN_CHARACTERS
           for c in login):
        raise InvalidFormat(_f("User login contains forbidden characters"))
    return login

def project_name(name):
    if not name:
        raise InvalidFormat(_f("Project name cannot be empty"))
    if len(name) > 50:
        raise InvalidFormat(_f("Project name is too long"))

def tag_path(path):
    if not path:
        raise InvalidFormat(_f("Tag path cannot be empty"))
    if len(path) > 200:
        raise InvalidFormat(_f("Tag path is too long"))

def document_name(name):
    if not name:
        raise InvalidFormat(_f("Document name cannot be empty"))
    if len(name) > 50:
        raise InvalidFormat(_f("Document name is too long"))

def tag_description(description):
    if len(description) > 102400:
        raise InvalidFormat(_f("Tag description is too long"))

def user_email(email):
    if not email:
        raise InvalidFormat(_f("Email cannot be empty"))  # but it can be NULL
    if '@' not in email:
        raise InvalidFormat(_f("Invalid email address"))