old_contents: # -*- coding: utf-8 -*-
  from flask_wtf import Form
  from wtforms import StringField, validators
  
  
  class ShortenedUrlForm(Form):
      url = StringField(
          'Url to be shortened',
          [
              validators.DataRequired(),
              validators.URL(message="A valid url is required")
          ]
      )
  
new_contents: # -*- coding: utf-8 -*-
  from flask_wtf import Form
  from wtforms import StringField, validators
  
  from .validation import not_spam
  
  
  class ShortenedUrlForm(Form):
      url = StringField(
          'Url to be shortened',
          [
              validators.DataRequired(),
              validators.URL(message="A valid url is required"),
              not_spam
          ]
      )
  
subject: Add not_spam validator to forms.ShortenedUrlForm