如果只想执行代码if，address具有member streets，则可以测试一下:

If you want to execute the code only if the address has the member streets you can test for just that:

if (
    ($FileContent.address | Get-Member -MemberType NoteProperty -Name "streets") -ne $null
){
    $FileContent.address = $FileContent.address | Select-Object * -ExcludeProperty streets
}