public function getCustomer($code = null) {
		if ($this->getResponseType() != 'customers') {
			throw new CheddarGetter_Response_Exception("Can't get a customer from a response doc that isn't of type 'customers'", CheddarGetter_Response_Exception::USAGE_INVALID);
		}
		if (!$code && $this->getElementsByTagName('customer')->length > 1) {
			throw new CheddarGetter_Response_Exception("This response contains more than one customer so you need to provide the code for the customer you wish to get", CheddarGetter_Response_Exception::USAGE_INVALID);
		}
		if (!$code) {
			return current($this->toArray());
		}
		$array = $this->toArray();
		return $array[$code];
	}