'Get capacities for a cell.
:param cell_name: Name of the :class:`Cell` to get capacities for.
:rtype: :class:`Cell`'

def capacities(self, cell_name=None):

    path = [('%s/capacities' % cell_name), 'capacities'][(cell_name is None)]
    return self._get(('/os-cells/%s' % path), 'cell')
