@Override
    public void removeNetworkPolicy(String uid) {
        checkArgument(!Strings.isNullOrEmpty(uid), ERR_NULL_NETWORK_POLICY_UID);

        synchronized (this) {
            if (isNetworkPolicyInUse(uid)) {
                final String error = String.format(MSG_NETWORK_POLICY, uid, ERR_IN_USE);
                throw new IllegalStateException(error);
            }

            NetworkPolicy networkPolicy = k8sNetworkPolicyStore.removeNetworkPolicy(uid);

            if (networkPolicy != null) {
                log.info(String.format(MSG_NETWORK_POLICY,
                        networkPolicy.getMetadata().getName(), MSG_REMOVED));
            }
        }
    }
@Test(expected = IllegalArgumentException.class)
    public void testRemoveNetworkPolicyWithNull() {
        target.removeNetworkPolicy(null);
    }