'Lists all sizes
:return: A list of all configurable node sizes.
:rtype: ``list`` of :class:`NodeSize`'

def list_sizes(self):

    sizes = []
    for (key, values) in self.PROFIT_BRICKS_GENERIC_SIZES.items():
        node_size = self._to_node_size(values)
        sizes.append(node_size)
    return sizes
