Does this function do one thing only?

Is the following method considered to be doing one thing only?

I'm wondering about that since it takes an optional argument.

public function findErrors($name = null)
{
    if ($name) {
        return isset($this->errors[$name]) ? $this->errors[$name] : [];
    }

    return $this->errors ?: [];
}

If not, would it be better / matter to have it separated like the following:

public function findErrors()
{
    return $this->errors ?: [];
}

public function findErrorsOf($name)
{
    return isset($this->errors[$name]) ? $this->errors[$name] : [];
}