Public/Get-TrelloBoardMember.ps1

function Get-TrelloBoardMember {
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory, ValueFromPipelineByPropertyName)]
        [ValidateNotNullOrEmpty()]
        [Alias('Id')]
        [string]$BoardId
    )
    begin {
        $ErrorActionPreference = 'Stop'
    }
    process {
        try {
            $invApiParams = @{
                PathParameters = 'boards/{0}/members' -f $BoardId
            }
            
            Invoke-PowerTrelloApiCall @invApiParams
        } catch {
            Write-Error $_.Exception.Message
        }
    }
}