Best option for chucking around $I in Cest classes?

GuysInCest.php

<?php

class CheeseCest
{
    /**
     * A test.
     * 
     * @param AuthenticatedStepsInterface $I
     *   The Guy object being used to test.
     */
    public function testSomething(AuthenticatedStepsInterface $I)
    {
        $this->doSomethingInternal($I, 'some value');
    }
    
    /**
     * A helper/internal method.
     * 
     * @param AuthenticatedStepsInterface $I
     *   The Guy object being used to test.
     * @param string $something
     *   Some random parameter we need.
     */
    protected function doSomethingInternal(AuthenticatedStepsInterface $I, $something)
    {
        $I->see($something);
        // ...
    }
}

// OR:

class CheeseCest
{
    /**
     * @var AuthenticatedStepsInterface
     *   Store the Guy object being used to test.
     */
    protected $guy;
    
    /**
     * A test.
     * 
     * @param AuthenticatedStepsInterface $I
     *   The Guy object being used to test.
     */
    public function testSomething(AuthenticatedStepsInterface $I)
    {
        $this->guy = $I;
        $this->doSomethingInternal($I, 'some value');
    }

    /**
     * A helper/internal method.
     *
     * @param string $something
     *   Some random parameter we need.
     */
    protected function doSomethingInternal($something)
    {
        $I = $this->guy;
        $I->see($something);
        // ...
    }
}