school: refactored group_show view

school/views.py

 from datetime import datetime
+from itertools import chain
 from django.core.exceptions import PermissionDenied, ValidationError
 from django.conf import settings
 from django.contrib.auth.decorators import login_required
@@ -153,27 +154,24 @@ def language(request, lang):
 def group_show(request, gid):
     user = request.user
     group = get_object_or_404(Group, id=gid)
-    mytemplates = [
-        t for t in Template.objects.filter(owner=request.user).all()]
-    noshare = True
-    for i, t in enumerate(mytemplates):
+
+    mytemplates = Template.objects.filter(owner=request.user, state='READY')
+    for t in mytemplates:
         t.myshares = t.share_set.filter(group=group)
-        if t.myshares.exists():
-            noshare = False
-        mytemplates[i] = t
-    publictemplates = [
-        t for t in Template.objects.filter(public=True, state='READY').all()]
-    for i, t in enumerate(publictemplates):
+
+    publictemplates = Template.objects.filter(public=True, state='READY')
+    for t in publictemplates:
         t.myshares = t.share_set.filter(group=group)
-        if t.myshares.exists():
-            noshare = False
-        publictemplates[i] = t
+
+    all_templates = chain(mytemplates, publictemplates)
+    has_share = any([t.myshares.exists() for t in all_templates])
+
     return render_to_response("show-group.html", RequestContext(request, {
         'group': group,
         'members': group.members.all(),
         'mytemplates': mytemplates,
         'publictemplates': publictemplates,
-        'noshare': noshare,
+        'noshare': not has_share,
         'userdetails': UserCloudDetails.objects.get(user=request.user),
         'owners': group.owners.all(),
     }))