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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _post_clean(self):
 """Run password validaton after clean methods When clean methods are run, the user instance does not yet exist. To properly compare model values agains the password (in the UserAttributeSimilarityValidator), we wait until we have an instance to compare against. https://code.djangoproject.com/ticket/28127 https://github.com/django/django/pull/8408 Has no effect in Django prior to 1.9 May become unnecessary in Django 2.0 (if this superclass changes) """

        super()._post_clean()  # updates self.instance with form data
        password = self.cleaned_data.get('password1')
        if password:
            try:
                password_validation.validate_password(password, self.instance)
            except ValidationError as error:
                self.add_error('password1', error)