diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index a86f529..500b9e8 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -4,10 +4,10 @@ Changelog
 Only important changes are mentioned below.
 
 
-v0.2 (unreleased)
+v0.2 (2015-01-30)
 -----------------
 
-* ...
+* Fixed problem with assertion on django.forms.ModelForm
 
 
 v0.1 (2015-01-21)
diff --git a/formaldehyde/fieldsets.py b/formaldehyde/fieldsets.py
index 85289df..a1c3656 100644
--- a/formaldehyde/fieldsets.py
+++ b/formaldehyde/fieldsets.py
@@ -1,5 +1,4 @@
 from __future__ import unicode_literals
-import itertools
 from django import forms
 from django.utils import six
 
@@ -86,7 +85,7 @@ def next(self):
 #==============================================================================
 class FieldsetFormMixin(object):
     def fieldsets(self):
-        assert(isinstance(self, forms.Form))
+        assert(isinstance(self, forms.BaseForm))
         
         meta = getattr(self, 'MetaForm', None)
         if not meta or not meta.fieldsets:
diff --git a/formaldehyde/readonly.py b/formaldehyde/readonly.py
index 8357ee1..b68ea3e 100644
--- a/formaldehyde/readonly.py
+++ b/formaldehyde/readonly.py
@@ -9,6 +9,7 @@ class ReadonlyFormMixin(object):
     """
 
     def set_readonly(self, is_readonly=True):
-        assert(isinstance(self, forms.Form))
+        assert(isinstance(self, forms.BaseForm))
+
         for field in self.fields:
             self.fields[field].is_readonly = is_readonly
diff --git a/formaldehyde/tests/test.py b/formaldehyde/tests/test.py
index 0d94d40..9e8f1a5 100644
--- a/formaldehyde/tests/test.py
+++ b/formaldehyde/tests/test.py
@@ -56,6 +56,13 @@ class TestFieldsetFormRaises(FieldsetFormMixin):
 class TestReadonlyForm(ReadonlyFormMixin, forms.Form):
     first_name = forms.CharField(label='First name', max_length=100)
 
+class TestReadonlyModelForm(ReadonlyFormMixin, forms.ModelForm):
+    first_name = forms.CharField(label='First name', max_length=100)
+
+    class Meta:
+        model = ContentType
+        fields = "__all__"
+
 class TestWhitespaceForm(StripWhitespaceFormMixin, forms.Form):
     first_name = forms.CharField(label='First name', max_length=100)
     last_name = forms.CharField(label='Last name', max_length=100)
@@ -64,6 +71,18 @@ def full_clean(self):
         self.strip_whitespace_from_data()
         super(TestWhitespaceForm, self).full_clean()
 
+class TestWhitespaceModelForm(StripWhitespaceFormMixin, forms.ModelForm):
+    first_name = forms.CharField(label='First name', max_length=100)
+    last_name = forms.CharField(label='Last name', max_length=100)
+
+    class Meta:
+        model = ContentType
+        fields = "__all__"
+
+    def full_clean(self):
+        self.strip_whitespace_from_data()
+        super(TestWhitespaceForm, self).full_clean()
+
 
 #==============================================================================
 class FormalehydeTestCase(TestCase):
@@ -114,24 +133,35 @@ def test_fieldset_model_form(self):
     def test_raises_form(self):
         form = TestFieldsetFormRaises()
         fieldsets = form.fieldsets()
-
         with self.assertRaises(AssertionError):
             six.next(fieldsets)
 
     def test_readonly_form(self):
         form = TestReadonlyForm()
-
         form.set_readonly(True)
         self.assertTrue(form.fields['first_name'].is_readonly)
+        form.set_readonly(False)
+        self.assertFalse(form.fields['first_name'].is_readonly)
 
+    def test_readonly_model_form(self):
+        form = TestReadonlyModelForm()
+        form.set_readonly(True)
+        self.assertTrue(form.fields['first_name'].is_readonly)
         form.set_readonly(False)
         self.assertFalse(form.fields['first_name'].is_readonly)
 
     def test_whitespace_form(self):
         form = TestWhitespaceForm(data={'first_name': ' John    ', 'last_name': '   '})
         self.assertFalse(form.is_valid())
-
         form = TestWhitespaceForm(data={'first_name': ' Foo    ', 'last_name': '   Bar ack'})
         self.assertTrue(form.is_valid())
         self.assertEqual(form.cleaned_data['first_name'], 'Foo')
         self.assertEqual(form.cleaned_data['last_name'], 'Bar ack')
+
+    def test_whitespace_model_form(self):
+        form = TestWhitespaceModelForm(data={'first_name': ' John    ', 'last_name': '   '})
+        self.assertFalse(form.is_valid())
+        form = TestWhitespaceModelForm(data={'first_name': ' Foo    ', 'last_name': '   Bar ack'})
+        self.assertTrue(form.is_valid())
+        self.assertEqual(form.cleaned_data['first_name'], 'Foo')
+        self.assertEqual(form.cleaned_data['last_name'], 'Bar ack')
diff --git a/formaldehyde/whitespace.py b/formaldehyde/whitespace.py
index b3dd6a2..d859a96 100644
--- a/formaldehyde/whitespace.py
+++ b/formaldehyde/whitespace.py
@@ -10,7 +10,7 @@ class StripWhitespaceFormMixin(object):
     """
 
     def strip_whitespace_from_data(self):
-        assert(isinstance(self, forms.Form))
+        assert(isinstance(self, forms.BaseForm))
 
         if hasattr(self, 'data') and self.data:
             data = self.data.copy()