Swagger doc: array input needed

Product: PowerShell Universal
Version: 4.5.3

I have an API that takes [string [ `] ] $OwnerUPN as input. I defined the docstring above the API to for it to generate a swagger doc. However, on the swaggerUI, this parameter takes a string input instead of an array input.
example: if passed upn1,upn2
via swagger it sends “upn1,upn2” instead of “upn1”,“upn2”
is there any documentation to define the schema of swagger? Thank you

.PARAMETER OwnerUPN
The User Principal Name (UPN) of one or more owners of the app. 
...
param (
    
    [Parameter(Mandatory)]
    [ValidatePattern('^[a-zA-Z0-9._%+-]+@($')]
    [ValidateNotNullorEmpty()]
    [string[]]$OwnerUPN,

)