yielded copies of dicts to prevent polution

inventory_provider/db/ims_data.py

@@ -124,6 +124,14 @@ def get_port_id_services(ds: IMS):
     # internal port a / internal port b
     # port a / port b
 
+    # if there are more than two ports we'll yield a circuit of the ends of the
+    # sequence and the reverse; and then single ended circuits for all ports
+    # between
+    # e.g. four ports are reported [a,b,c,d] the 4 circs would have endpoints
+    # a and d
+    # d and a
+    # b only
+    # c only
     def _populate_end_info(_circuit, _port_ids):
         port_ids = [p for p in _port_ids if p]
         if not port_ids:
@@ -133,15 +141,15 @@ def get_port_id_services(ds: IMS):
         _circuit['port_a_id'] = port_a_id
         if port_a_id != port_b_id:
             _circuit['port_b_id'] = port_b_id
-            yield _circuit
+            yield copy(_circuit)
             _circuit['port_a_id'], _circuit['port_b_id'] = \
                 _circuit['port_b_id'], _circuit['port_a_id']
-        yield _circuit
+        yield copy(_circuit)
         if len(port_ids) > 2:
             _circuit.pop('port_b_id', None)
             for p in port_ids[1:-1]:
                 _circuit['port_a_id'] = p
-                yield _circuit
+                yield copy(_circuit)
 
     for circuit in circuits:
         cd = {