text: from flask_wtf import FlaskForm
  from wtforms import StringField, PasswordField, SubmitField, BooleanField, widgets, SelectMultipleField
  from wtforms.validators import DataRequired, Length, Email, EqualTo
  
  class RegistrationForm(FlaskForm):
      username = StringField("Username",
          validators=[DataRequired(), Length(min=2, max=90)])
      email = StringField("Email", 
          validators=[DataRequired(), Email()])
      password = PasswordField("Password", validators=[DataRequired()])
      confirm_password = PasswordField("Confirm Password", 
          validators=[DataRequired(), EqualTo("password")])
  
      submit = SubmitField("Sign Up")
  
  class LoginForm(FlaskForm):
      email = StringField("Email", 
          validators=[DataRequired(), Email()])
      password = PasswordField("Password", validators=[DataRequired()])
      remember = BooleanField("Remember me")
      submit = SubmitField("Login")
  
  class MultiCheckboxField(SelectMultipleField):
      widget = widgets.ListWidget(prefix_label=False)
      option_widget = widgets.CheckboxInput()
  
  class SimpleForm(FlaskForm):
      # string_of_files = ['one\r\ntwo\r\nthree\r\n']
      # list_of_files = string_of_files[0].split()
      # # create a list of value/description tuples
      
      article_numbers = ["0", "1", "2", "3", "4"]
      numbers = [(x, x) for x in article_numbers]
      example = MultiCheckboxField('Label', choices=numbers)
      