def delete_tag(self, tag_name):
tag = session.query(Tag).filter_by(name=tag_name).first()
if tag in self.tags:
self.tags.remove(tag)
self.save()
if tag.count == 1:
session.delete(tag)
else:
tag.count = Tag.count - 1
session.commit()
def save(self):
session.add(self)
session.commit()
