public boolean checkReturnTypes(String returnTypes) {
        if (errorCode != ErrorCode.NONE) {
            return false;
        }
        if (returnValues.satisfies(returnTypes)) {
            return true;
        }
        setError(ErrorCode.WRONG_RETURN, "checkReturnValues: Wrong return values");
        return false;
    }
Check if this Request contains return types compatible with the
given type string. If this Request contains an error it is
considered incompatible with all possible type strings. If the
return values are not compatible with the given type string and
an error condition is not set, the {@link
ErrorCode#WRONG_RETURN} error will be set. This method is
intended to be used by the RPC client after a method has been
invoked to verify the return value types. Please refer to the
{@link Method} class description for an explanation of type
strings.

@return true if all is ok and the return types are compatible
with 'returnTypes'
@param returnTypes type string
jrt/src/com/yahoo/jrt/Request.java