MAAS custom testing scripts

Hello. I want to pass some data to test script through API. What i do wrong?

I need
POST /MAAS/api/2.0/machines/{system_id}/op-test
‘enable_ssh’=>‘True’,
‘parameters’=>‘foo=SomeData’,
‘testing_scripts’ => ‘example’,
And inside script ‘example’
echo “$1” returns ‘SomeData’

My test 1:

#!/bin/bash
# --- Start MAAS 1.0 script metadata ---
# name: 100_example
# parallel: instance
# parameters:
#   foo: {type: storage}
# --- End MAAS 1.0 script metadata ---
echo "0: $0"
echo "1: $1"

POST /MAAS/api/2.0/machines/{system_id}/op-test
‘enable_ssh’=>‘True’,
‘parameters’=>‘foo=/dev/sdc’,
‘testing_scripts’ => ‘100_example’,
This API query runs script for every storage in server.
(sda, sdb, sdc, sdd), not only on sdc. WHY?

My test 2:
If i chande → foo: {type: url}

#!/bin/bash
# --- Start MAAS 1.0 script metadata ---
# name: 101_example
# parallel: instance
# parameters:
#   foo: {type: url}
# --- End MAAS 1.0 script metadata ---
echo "0: $0"
echo "1: $1"

POST /MAAS/api/2.0/machines/{system_id}/op-test
‘enable_ssh’=>‘True’,
‘parameters’=>‘foo=https://www.google.com/’,
‘testing_scripts’ => ‘101_example’,
This API query runs script 1 time. But $1 is empty.