public void putMap(Map<String, String> map)
    {
        if (map == null) {
            putNumber1(0);
        }
        else {
            Utils.checkArgument(map.size() < 256, "Map has to be smaller than 256 elements");
            putNumber1(map.size());
            for (Entry<String, String> entry : map.entrySet()) {
                if (entry.getKey().contains("=")) {
                    throw new IllegalArgumentException("Keys cannot contain '=' sign. " + entry);
                }
                if (entry.getValue().contains("=")) {
                    throw new IllegalArgumentException("Values cannot contain '=' sign. " + entry);
                }
                String val = entry.getKey() + "=" + entry.getValue();
                putString(val);
            }
        }
    }
@Test(expected = IllegalArgumentException.class)
    public void testMapIncorrectKey()
    {
        ZFrame frame = new ZFrame(new byte[(1 + 10)]);
        ZNeedle needle = new ZNeedle(frame);

        Map<String, String> map = new HashMap<>();
        map.put("ke=", "value");
        needle.putMap(map);
    }