Apache Nifi: set empty string as value of variable with nifi-toolkit cli

[#1]

Hi guys!

How to set empty string value with nifi-toolkit pg-set-var at apache nifi

./nifi-toolkit-1.10.0/bin/cli.sh nifi pg-set-var -pgid  $pg_id -var stand -val "" -u $host_name

This code returns error 

ERROR: Error executing command 'pg-set-var' : Missing required option --varValue