add a total lumped loss in metrics

Author: saadrazaa

gnpy/core/elements.py

@@ -474,6 +474,7 @@ def to_response_element_json(self):
             { 'metric-type': 'Total Loss', 'metric-unit': 'dB', 'metric-value': self.loss},
             { 'metric-type': 'Connection In', 'metric-unit': 'dB', 'metric-value': self.params.con_in},
             { 'metric-type': 'Connection Out + EOL', 'metric-unit': 'dB', 'metric-value': self.params.con_out},
+            { 'metric-type': 'Lumped Losses', 'metric-unit': 'dB', 'metric-value': sum(array([lumped['loss'] for lumped in self.params.lumped_losses]))},
             { 'metric-type': 'Power Out Per Channel', 'metric-unit': 'dBm', 'metric-value': self.pch_out_db}
         ]