def __getitem__(self, key):
        val = dict.__getitem__(self, key)
        if self.main.interpolation: 
            if isinstance(val, basestring):
                return self._interpolate(key, val)
            if isinstance(val, list):
                def _check(entry):
                    if isinstance(entry, basestring):
                        return self._interpolate(key, entry)
                    return entry
                new = [_check(entry) for entry in val]
                if new != val:
                    return new
        return val
Fetch the item and do string interpolation.
dataset/ETHPy150Open boakley/robotframework-workbench/rwb/lib/configobj.py/Section.__getitem__