code: def GetHashData(hashable):
          
          ms = StreamManager.GetStream()
          writer = BinaryWriter(ms)
          hashable.SerializeUnsigned(writer)
          ms.flush()
          retVal = ms.ToArray()
          StreamManager.ReleaseStream(ms)
          return retVal
docs: Get the data used for hashing.
  
          Args:
              hashable (neo.IO.Mixins.SerializableMixin): object extending SerializableMixin
  
          Returns:
              bytes: