old_contents: from flask_wtf import FlaskForm
  from wtforms import StringField, BooleanField, TextAreaField
  from wtforms.validators import DataRequired, Length
  
  class LoginForm(FlaskForm):
  	#: the DataRequired import is a validator, a function that
  	#: can be attached to a field to perform validation on the
  	#: data submitted by the user. The DataRequired validator
  	#: simply checks that the field is not submitted empty.
  	openid = StringField('openid', validators=[DataRequired()])
  	remember_me = BooleanField('remember_me', default=False)
  
  class EditForm(FlaskForm):
  	nickname = StringField('nickname', validators=[DataRequired()])
  	about_me = TextAreaField('about_me', validators=[Length(min=0, max=140)])
new_contents: from flask_wtf import FlaskForm
  from wtforms import StringField, BooleanField, TextAreaField
  from wtforms.validators import DataRequired, Length
  
  class LoginForm(FlaskForm):
  	#: the DataRequired import is a validator, a function that
  	#: can be attached to a field to perform validation on the
  	#: data submitted by the user. The DataRequired validator
  	#: simply checks that the field is not submitted empty.
  	openid = StringField('openid', validators=[DataRequired()])
  	remember_me = BooleanField('remember_me', default=False)
  
  class EditForm(FlaskForm):
  	nickname = StringField('nickname', validators=[DataRequired()])
  	about_me = TextAreaField('about_me', validators=[Length(min=0, max=140)])
  
  	def __init__(self, original_nickname, *args, **kwargs):
  		FlaskForm.__init__(self, *args, **kwargs)
  		self.original_nickname = original_nickname
  
  	def validate(self):
  		if not FlaskForm.validate(self):
  			return False
  		if self.nickname.data == self.original_nickname:
  			return True
  		user = User.query.filter_by(nickname=self.nickname.data).first()
  		if user != None:
  			self.nickname.errors.append('This nickname is already in use. \
  			                            Please choose another one.')
  			return False
  		return True
subject: update forms