Unresolved reference: query　（Android Kotlin)

Thanks for read this question. I'm new to Android development.

In my project,I'm trying to access video file in shared storage.

To accomplished the purpose,I wrote the below code. In the code, ContentResolver's query method is unresolved.I don't understand why.

 val query = ContentResolver.query( <-Unresolved
        collection,
        projection,
        selection,
        selectionArgs,
        sortOrder
    )
    query?.use{
        cursor ->
        val idColumn = cursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID)
        val nameColumn = cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DISPLAY_NAME)
        val durationColumn = cursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE)
        while(cursor.movieToNext()){
            val id = cursor.getLong(idColumn)
            val name = cursor.getString(nameColumn)
            val duration = cursor.getInt(durationColumn)
            val size = cursor.getInt(sizeColumn)

            val contentUri: Uri = ContentUris.withAppendedId(
                MediaStore.Video.Media.EXTERNAL_CONTENT_URI,
                id)
            videoList += Video(contentUri, name, duration, size)
        }

So coule someone please explaine to me the reason.Thank you.