Polimorphism example using Django's ModelForm

django_forms_polimorph.py

class QuotationForm(forms.ModelForm):

class Meta:
    model = Quotation
    fields = ('client','date_create', 'date_update', 'house_type',
    'house_set',
    )

def __init__(self, *args, **kwargs):
    self.request = kwargs.get('request')
    super().__init__()

def save(self, *args, **kwargs):
    # A parte importante
    self.cleaned_data['client'] = self.request.user
    super().save(*args, **kwargs)