queryset con django

[ichibi]

mmmmmmmmmmmmm ok ...
pero ahora lo hise >>> from datetime import timedelta
>>> from django.db.models import F
>>> from aplicacion.models import Proyecto, Componente, Alerta
>>> qs= Alerta.objects.filter(proyecto__nombre='Proyeto1', componente__nombre='guardar')
>>> alerta_list= qs.filter(fecha__gte=F('fecha') - timedelta(weeks=5))

y luego le di un print y me salio lo siguente ...

>>> print alerta_list
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "/usr/lib/python2.5/site-packages/django/db/models/query.py", line 68, in __repr__
data = list(self[:REPR_OUTPUT_SIZE + 1])
File "/usr/lib/python2.5/site-packages/django/db/models/query.py", line 83, in __len__
self._result_cache.extend(list(self._iter))
File "/usr/lib/python2.5/site-packages/django/db/models/query.py", line 269, in iterator
for row in compiler.results_iter():
File "/usr/lib/python2.5/site-packages/django/db/models/sql/compiler.py", line 672, in results_iter
for rows in self.execute_sql(MULTI):
File "/usr/lib/python2.5/site-packages/django/db/models/sql/compiler.py", line 727, in execute_sql
cursor.execute(sql, params)
File "/usr/lib/python2.5/site-packages/django/db/backends/util.py", line 15, in execute
return self.cursor.execute(sql, params)
File "/usr/lib/python2.5/site-packages/django/db/backends/sqlite3/base.py", line 200, in execute
return Database.Cursor.execute(self, query, params)
InterfaceError: Error binding parameter 2 - probably unsupported type.


disculpame si de pronto hago preguntas tontas pero como te dije soy nueva en django