src/XdrModel/Operation/SetOptionsOp.php
public function setAuthRevocable($isRevocable)
    {
        if ($isRevocable) {
            $this->setFlags   = $this->setFlags | static::FLAG_AUTH_REVOCABLE;
            $this->clearFlags = $this->clearFlags & ~(static::FLAG_AUTH_REVOCABLE);
        }
        else {
            $this->setFlags   = $this->setFlags & ~(static::FLAG_AUTH_REVOCABLE);
            $this->clearFlags = $this->clearFlags | static::FLAG_AUTH_REVOCABLE;
        }

        return $this;
    }
public function setAuthRevocable($isRevocable)
    {
        if ($isRevocable) {
            $this->setFlags   = $this->setFlags | static::FLAG_AUTH_REVOCABLE;
            $this->clearFlags = $this->clearFlags & ~(static::FLAG_AUTH_REVOCABLE);
        }
        else {
            $this->setFlags   = $this->setFlags & ~(static::FLAG_AUTH_REVOCABLE);
            $this->clearFlags = $this->clearFlags | static::FLAG_AUTH_REVOCABLE;
        }

        return $this;
    }
If set, the authorized flag in TrustLines can be cleared. Otherwise, authorization cannot be revoked

@param $isRevocable
@return SetOptionsOp