src/Option.php
public function pushValue($value)
    {
        $value = $this->_preprocessValue($value);
        $this->value[] = $value;
        $this->callTrigger();
    }
public function pushValue($value)
    {
        $value = $this->_preprocessValue($value);
        $this->value[] = $value;
        $this->callTrigger();
    }
push option value, when the option accept multiple values.

@param mixed