<p>After my <code>form.Form</code> validates the user input values I pass them to a separate (external) process for further processing. This external process can potentially find further errors in the values.</p>

<p>Is there a way to inject these errors into the already validated form so they can be displayed via the usual form error display methods (or are there better alternative approaches)?</p>

<p>One suggestions was to include the external processing in the form validation, which is not ideal because the external process does a lot more than merely validate.</p>

You can add additional error details to the form's
```
_errors
```
attribute directly:
https://docs.djangoproject.com/en/1.5/ref/forms/validation/#described-later
https://docs.djangoproject.com/en/1.6/ref/forms/validation/#modifying-field-errors