Drop support for Django <1.8, Python <2.7

polymorphic/formsets/generic.py

@@ -1,15 +1,11 @@
 import django
+from django.contrib.contenttypes.forms import BaseGenericInlineFormSet, generic_inlineformset_factory
 from django.contrib.contenttypes.models import ContentType
 from django.db import models
 from django.forms.models import ModelForm
 
 from .models import BasePolymorphicModelFormSet, polymorphic_child_forms_factory, PolymorphicFormSetChild
 
-try:
-    from django.contrib.contenttypes.forms import BaseGenericInlineFormSet, generic_inlineformset_factory  # Django 1.7+
-except ImportError:
-    from django.contrib.contenttypes.generic import BaseGenericInlineFormSet, generic_inlineformset_factory
-
 
 class GenericPolymorphicFormSetChild(PolymorphicFormSetChild):
     """

polymorphic/formsets/models.py

@@ -1,3 +1,4 @@
+from collections import OrderedDict
 
 import django
 from django import forms
@@ -7,11 +8,6 @@ from django.forms.models import ModelForm, BaseModelFormSet, BaseInlineFormSet,
 from django.utils.functional import cached_property
 from .utils import add_media
 
-try:
-    from collections import OrderedDict
-except ImportError:
-    from django.utils.datastructures import SortedDict as OrderedDict  # Python 2.6
-
 
 class PolymorphicFormSetChild(object):
     """