library/Rediska/Key/List.php
public function insertBefore($referenceValue, $value)
    {
        return $this->_getRediskaOn()->insertToListBefore($this->getName(), $referenceValue, $value);
    }
public function insertBefore($referenceValue, $value)
    {
        return $this->_getRediskaOn()->insertToListBefore($this->getName(), $referenceValue, $value);
    }
Insert a new value as the element before the reference value

@param mixed   $referenceValue Reference value
@param mixed   $value          Value
@return integer|boolean