Public/Get-TrelloCardAttachment.ps1

function Get-TrelloCardAttachment {
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory, ValueFromPipeline)]
        [ValidateNotNullOrEmpty()]
        [object]$Card,
    
        [Parameter()]
        [ValidateNotNullOrEmpty()]
        [string]$Name
    )
    begin {
        $ErrorActionPreference = 'Stop'
    }
    process {
        try {
            $params = @{
                'Uri' = "$script:baseUrl/cards/{0}/attachments?{1}" -f $Card.Id, $trelloConfig.String
            }
            $attachments = Invoke-RestMethod @params
            if ($PSBoundParameters.ContainsKey('Name')) {
                $attachments | Where-Object { $_.name -eq $Name }
            } else {
                $attachments    
            }
        } catch {
            Write-Error $_.Exception.Message
        }
    }
}