Review feedback: docstrings, move out form

src/registrar/forms/__init__.py

@@ -1 +1,2 @@
 from .application_wizard import *
+from .domain import DomainAddUserForm

src/registrar/forms/domain.py

@@ -0,0 +1,21 @@
+"""Forms for domain management."""
+
+from django import forms
+
+from registrar.models import User
+
+
+class DomainAddUserForm(forms.Form):
+
+    """Form for adding a user to a domain."""
+
+    email = forms.EmailField(label="Email")
+
+    def clean_email(self):
+        requested_email = self.cleaned_data["email"]
+        try:
+            User.objects.get(email=requested_email)
+        except User.DoesNotExist:
+            # TODO: send an invitation email to a non-existent user
+            raise forms.ValidationError("That user does not exist in this system.")
+        return requested_email

src/registrar/views/domain.py

@@ -14,12 +14,18 @@ from .utility import DomainPermission
 
 
 class DomainView(DomainPermission, DetailView):
+
+    """Domain detail overview page."""
+
     model = Domain
     template_name = "domain_detail.html"
     context_object_name = "domain"
 
 
 class DomainUsersView(DomainPermission, DetailView):
+
+    """User management page in the domain details."""
+
     model = Domain
     template_name = "domain_users.html"
     context_object_name = "domain"
@@ -42,6 +48,13 @@ class DomainAddUserForm(DomainPermission, forms.Form):
 
 
 class DomainAddUserView(DomainPermission, FormMixin, DetailView):
+
+    """Inside of a domain's user management, a form for adding users.
+
+    Multiple inheritance is used here for permissions, form handling, and
+    details of the individual domain.
+    """
+
     template_name = "domain_add_user.html"
     model = Domain
     form_class = DomainAddUserForm