forms.py

from wtforms import SubmitField, StringField, PasswordField, BooleanField,  HiddenField, validators
from flask_wtf import FlaskForm


class LoginForm(FlaskForm):
    username = StringField("Username", validators=[validators.input_required()],)
    password = PasswordField("Password", validators=[validators.input_required()])
    challenge = HiddenField("challenge")
    remember = BooleanField("Remember me")
    submit = SubmitField("Sign in")