Subclassing list
<p>I want create a DataSet class which is basically a list of samples.
But I need to override each insertion operation to the DataSet.</p>

<p>Is there any simple way to do this without writing my own append, extend, iadd etc. ?</p>

<p><strong>UPDATE:</strong> I want to add a backpointer to each sample, holding index of the sample in the DataSet. This is needed to the processing algorithm I use. I have a solution, but it seems unelegant - a renumber() function -- it ensures that the backpointers are valid.</p>
