'Fetch data on a local area network
:param  ex_href: The href of the lan you wish to describe.
:type   ex_href: ``str``
:param  ex_datacenter_id: The ID of the parent
datacenter for the LAN.
:type   ex_datacenter_id: ``str``
:param  ex_lan_id: The ID of LAN.
:type   ex_lan_id: ``str``
:return:    Instance class ``ProfitBricksLan``
:rtype:     :class:`ProfitBricksLan`'

def ex_describe_lan(self, ex_href=None, ex_datacenter_id=None, ex_lan_id=None):

    use_full_url = True
    if (ex_href is None):
        if ((ex_datacenter_id is None) or (ex_lan_id is None)):
            raise ValueError('IDs    for    the    data    center    and    LAN    are    required.')
        else:
            use_full_url = False
            ex_href = 'datacenters/{datacenter_id}/lans/{lan_id}'.format(datacenter_id=ex_datacenter_id, lan_id=ex_lan_id)
    response = self.connection.request(action=ex_href, method='GET', params={'depth': 1}, with_full_url=use_full_url)
    return self._to_lan(response.object)
