FormsetField.py

class FormsetWidget(forms.Widget):
    def render(self, name, value, attrs):
        if isinstance(value, self.formset):
            formset = value
        else:
            formset = self.formset(initial=value, prefix=name)

        return render_to_string(self.template, {'formset': formset})

    def value_from_datadict(self, data, files, name):
        formset = self.formset(data=data, prefix=name)
        return formset


class FormsetField(forms.Field):
    widget = FormsetWidget

    def __init__(self, formset=formsets.BaseFormSet, form=forms.Form, extra=0,
                    template='admin/formset_widget.html', *args, **kwargs):
        self.formset = formsets.formset_factory(form, formset=formset, extra=extra)
        self.template = template

        super(FormsetField, self).__init__(*args, **kwargs)

        self.widget.formset = self.formset
        self.widget.template = self.template

    def clean(self, value):
        # value -- объект формсета
        if not value.is_valid():
            raise forms.ValidationError(value.errors)
        return value.cleaned_data