'List virtual networks on a provider.
:param location: Location from which to request a list of virtual
networks. (optional)
:type  location: :class:`NodeLocation`
:return: List of virtual networks available to be connected to a
compute node.
:rtype:  ``list`` of :class:`OpenNebulaNetwork`'

def ex_list_networks(self, location=None):

    return self._to_networks(self.connection.request('/network').object)
