How to change dynamically at runtime the collection?
<?php 
class Robots extends \Phalcon\Mvc\Collection {
    $_sourceName = 'robots';
    function setSource($xpto){
                $this->_sourceName = 'robots_'.$xpto;
    }
    function getSource(){
                return $this->_sourceName;
    }
    function findConditions($xpto, $conditions){
                $this->setSource($xpto);
                return $this->find(['conditions' => $conditions];)
    }
}