powershell invoke rest api toward AWX - powershell

Question

I'm struggling for last week or more with sending rest api command from powershell to add host in AWX(from curl is working). When I sent one parameter is worki but I need to send also variables
$headers = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"
$headers.Add("Authorization", "Basic $VfAwxTokenX")
$Headers.Add('Content-Type', 'application/json')
$body = #{
name = '$vmname'
variables = 'test'
}| ConvertTo-Json
write-output $body
$response = Invoke-RestMethod 'https://awx/api/v2/inventories/2/hosts/' -Method 'POST' -Headers $headers -UseBasicParsing -Body $body
and error what i get:
{
"name": "wewewe",
"variables": "test" } Invoke-RestMethod : {"variables":["Cannot parse as JSON (error: Expecting value: line 1 column 1 (char 0)) or
YAML (error: Input type str is not a dictionary)."]} At line:32
char:13
$response = Invoke-RestMethod 'https://awx/api ...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CategoryInfo : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod],
WebException
FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand
Maybe any one of users had that issue and now how to overcome it?

Answer 1

According to my research, the parameter variables should be defined as JSON or YAML format. For more details, please refer to here.
For more details about how to call the API, please refer to the blog.

Answer 2

the problem was prosaic
variables = 'test'
if i put anything else then test is working :/