A small class for django form that allow to create Form field from Model when you are not using a ModelForm

forms.py

class FieldBuilder(object):
    """Return the default form field for a model field.  This field will be validated oin the same
    way as the form field would be on a ModelForm.
    Optionally, extra kwargs can be added to override what the form field is initialized with.

    So this:

        class ExampleForm(forms.ModelForm):
            class Meta:
                model = ExampleModel
                fields = ['example_field']

    is equivalent to:

        class ExampleForm(forms.Form):
            example_field = FieldBuilder(ExampleModel, 'example_field')

    Usage:

        class ExampleCreationForm(forms.Form):
            example_field = FieldBuilder(ExampleModel, 'example_field')
            # The original field in the model has blank=True, we can override it here
            different_field = FieldBuilder(AnotherExampleModel, 'different_field', required=True)

            def save(self):
                data = self.cleaned_data
                obj = ExampleModel(example_field=data['example_field'])
                obj2 = AnotherExampleModel(different_field=data['different_field'])
                obj.save()
                obj2.save()
    """
    def __new__(cls, model, field_name, **kwargs):
        model_field = model._meta.get_field(field_name)
        return model_field.formfield(**kwargs)