Cannot delete kubernetes namespace

add parameter

--grace-period=0 --force

if still cannot be deleted

echo $(kubectl config view --raw -oyaml | grep client-cert  |cut -d ' ' -f 6) |base64 -d > /tmp/client.pem
echo $(kubectl config view --raw -oyaml | grep client-key-data  |cut -d ' ' -f 6 ) |base64 -d > /tmp/client-key.pem
echo $(kubectl config view --raw -oyaml | grep certificate-authority-data  |cut -d ' ' -f 6  ) |base64 -d > /tmp/ca.pem

curl --cert /tmp/client.pem --key /tmp/client-key.pem --cacert /tmp/ca.pem -H "Content-Type: application/json" -X PUT --data-binary @/tmp/temp.json https://xxx.xxx.xxx.xxx:6443/api/v1/namespaces/<namespaces>/finalize