Godeps/_workspace/src/gopkg.in/mgo.v2/session.go
func (c *Collection) FindId(id interface{}) *Query {
	return c.Find(bson.D{{"_id", id}})
}
func (c *Collection) FindId(id interface{}) *Query {
	return c.Find(bson.D{{"_id", id}})
}
// FindId is a convenience helper equivalent to:
//
//     query := collection.Find(bson.M{"_id": id})
//
// See the Find method for more details.