I have form with one input for email and two submit buttons to subscribe and unsubscribe from newsletter:
<form action="" method="post">
{{ form_newsletter }}
<input type="submit" name="newsletter_sub" value="Subscribe" />
<input type="submit" name="newsletter_unsub" value="Unsubscribe" />
</form>
I have also class form:
class NewsletterForm(forms.ModelForm):
    class Meta:
        model = Newsletter
        fields = ('email',)
I must write my own clean_email method and I need to know by which button was form submited. But the value of submit buttons aren't in self.cleaned_data dictionary. Could I get values of buttons otherwise?