'org-openroadm-network-topology:OMS-attributes']['span']["engineered-spanloss"]
length = res['network'][0]['ietf-network-topology:link'][i][
'org-openroadm-network-topology:OMS-attributes']['span']['link-concatenation'][0]['SRLG-length']
'org-openroadm-network-topology:OMS-attributes']['span']["engineered-spanloss"]
length = res['network'][0]['ietf-network-topology:link'][i][
'org-openroadm-network-topology:OMS-attributes']['span']['link-concatenation'][0]['SRLG-length']