Python: how do I implement 'pop' in this class?
<p>I'd like this class to act like a list. It's data resides in the attribute self.data.
If I have an instance, pp = population, does defining <code>__getitem__</code> mean I can refer to 
pp instead of pp.data? Or is it the defining of <code>__repr__</code> that does that?
   Would deriving this class from list instead of object provide me with 'pop'.
Right now I need to implement 'pop'method.   Thanks</p>

<pre><code>class population (object):
def __init__ (self):
    self.data = []

def append(self, item):
    self.data.append(item)

def extend(self, item):
    self.data.extend(item)

def sort(self):
    self.data.sort(cmp=fitnesscompare)

def __getitem__(self, index): return self.data[index]

def __setitem__(self, index, item): self.data[index] = item

def __len__(self): return len(self.data)

def __repr__(self): return repr(self.data)

def copy(self):
    return copy.deepcopy(self)
</code></pre>
