'Lists available nodes sizes.
This overrides the EC2 default method in order to use Outscale
information or data.
:rtype: ``list`` of :class:`NodeSize`'

def list_sizes(self, location=None):

    available_types = self.region_details[self.region_name]['instance_types']
    sizes = []
    for instance_type in available_types:
        attributes = OUTSCALE_INSTANCE_TYPES[instance_type]
        attributes = copy.deepcopy(attributes)
        price = self._get_size_price(size_id=instance_type)
        attributes.update({'price': price})
        sizes.append(NodeSize(driver=self, **attributes))
    return sizes
