Merge pull request #1502 from marfire/doc_modelvalid

not be corrected by the user.

Note that ``full_clean()`` will *not* be called automatically when you call

your model's :meth:`~Model.save()` method, nor as a result of

:class:`~django.forms.ModelForm` validation. In the case of

:class:`~django.forms.ModelForm` validation, :meth:`Model.clean_fields()`,

:meth:`Model.clean()`, and :meth:`Model.validate_unique()` are all called

individually.

You'll need to call ``full_clean`` manually when you want to run one-step model

validation for your own manually created models. For example::

your model's :meth:`~Model.save()` method. You'll need to call it manually

when you want to run one-step model validation for your own manually created

models. For example::

    from django.core.exceptions import ValidationError

    try: