src/Container.php
public function setDefinition($id, Definition $definition)
    {
        $id = strtolower($id);

        $this->serviceDefinitions[$id] = $definition;

        return $this;
    }
public function setDefinition($id, Definition $definition)
    {
        $id = strtolower($id);

        $this->serviceDefinitions[$id] = $definition;

        return $this;
    }
Set service definition

@param string     $id         Service id
@param Definition $definition Service definition

@return Container