start =
  element CompleteMultipartUpload {
    element Part {
      element PartNumber { xsd:int } &
      element ETag { xsd:string } &
      element ChecksumCRC32 { xsd:string }? &
      element ChecksumCRC32C { xsd:string }? &
      element ChecksumCRC64NVME { xsd:string }? &
      element ChecksumSHA1 { xsd:string }? &
      element ChecksumSHA256 { xsd:string }?
    }+
  }
