def print_tree(self, cid, level=1, maxlevel=-1):
		collection = self.get_collection_with_id(cid)
		print hf.row_string([level, SQLHelper.get_node_str(collection, level)], 
			[9, 50])

		level = level + 1
		if maxlevel != -1 and level > maxlevel:
			return

		for child in self.get_child_collections_of_id(cid):
			self.print_tree(child.id, level, maxlevel)
def print_collection(instance):
	assert is_collection(instance)
	print hf.row_string([instance.id, instance.parent_id, instance.is_category, instance.name], 
			[6, 6, 10, 50])
	def get_node_str(collection, level=1):
		node_str = hf.row_string([collection.id, collection.parent_id, collection.name],
			[8, 8, 50])
		return node_str