def add(title, desc, father, icon):
assert isinstance(title, basestring), 'title is not string'
assert isinstance(desc, basestring), 'title is not string'
assert len(title) > 0, 'title name too short!'
assert len(desc) > 5, 'desc name too short!'
assert father is None or isinstance(father, ObjectId)
if father:
assert CategoryHelper.get(father)
new_category = Category()
new_category.title = title
new_category.desc = desc
if father:
new_category.father = father
if icon:
encoded = b64encode(icon.read())
new_category.icon.new_file()
new_category.icon.write(encoded)
new_category.icon.close()
new_category.save()
if father:
CategoryHelper.add_son(father, new_category.id)
return new_category
