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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def list_items(self, package_keyname, **kwargs):
 """List the items for the given package. :param str package_keyname: The package for which to get the items. :returns: List of items in the package """

        get_kwargs = {}
        get_kwargs['mask'] = kwargs.get('mask', ITEM_MASK)

        if 'filter' in kwargs:
            get_kwargs['filter'] = kwargs['filter']

        package = self.get_package_by_key(package_keyname, mask='id')
        items = self.package_svc.getItems(id=package['id'], **get_kwargs)
        return items