diff --git a/day20/day20.py b/day20/day20.py
index b4e85bb..191e223 100644
--- a/day20/day20.py
+++ b/day20/day20.py
@@ -51,16 +51,6 @@ def simulate(modules: dict[str, BaseModule]) -> tuple[int, int]:
     return low, high
 
 
-def get_final_gates(module_map: dict[str, BaseModule]) -> list[ConjunctionModule]:
-    """Should return vd, tp, pt, bk"""
-    result: list[ConjunctionModule] = []
-    for module in module_map.values():
-        if isinstance(module, ConjunctionModule) and len(module.inputs) >= 8:
-            result.append(module)
-    print([module.name for module in result])
-    return result
-
-
 def get_loop_paths(
     start_switch: str, module_map: dict[str, BaseModule]
 ) -> list[BaseModule]:
@@ -75,14 +65,15 @@ def get_loop_paths(
             current_module = module_map[current_module.outputs[0]]
         else:
             # return flipflop in outputs
-            flipflops = (
-                output
-                for output in current_module.outputs
-                if isinstance(module_map[output], FlipFlopModule)
-            )
-            current_module = module_map[next(flipflops)]
+            outputs: list[BaseModule] = [
+                module_map[output] for output in current_module.outputs
+            ]
+            filtered = [node for node in outputs if isinstance(node, FlipFlopModule)]
+            assert len(filtered) == 1
+            current_module = filtered[0]
 
     path.append(current_module)  # should be a ConjunctionModule
+    assert isinstance(current_module, ConjunctionModule)
     return path
 
 
@@ -108,13 +99,17 @@ def get_module_groups(module_map: dict[str, BaseModule]) -> ModuleGroups:
         get_loop_paths(node_name, module_map) for node_name in broadcaster.outputs
     ]
     loop_tails: list[ConjunctionModule] = []
+
+    # for each loop, the conjunction module goes to one other conjunction.
+    # grab this set of conjunctions, they are known as loop_tails
     for loop_path in loop_paths:
         last_node = loop_path[-1]
-        for node_name in last_node.outputs:
-            node = module_map[node_name]
-            if isinstance(node, ConjunctionModule):
-                loop_tails.append(node)
-                break
+
+        nodes = [module_map[node_name] for node_name in last_node.outputs]
+        filtered = [node for node in nodes if isinstance(node, ConjunctionModule)]
+        assert len(filtered) == 1
+        loop_tails.extend(filtered)
+
     last_join_name = loop_tails[0].outputs[0]
     last_conjunction = get_typed_module(module_map, last_join_name, ConjunctionModule)
     sink = get_typed_module(module_map, "rx", SinkModule)
diff --git a/day20/tests/test_day20.py b/day20/tests/test_day20.py
index ccbdbd2..b807e18 100644
--- a/day20/tests/test_day20.py
+++ b/day20/tests/test_day20.py
@@ -1,4 +1,4 @@
-from day20.day20 import FILE_A, FILE_B, part1
+from day20.day20 import FILE_A, FILE_B, FILE_PROD, part1, part2
 from day20.lib.parsers import get_modules
 
 
@@ -8,3 +8,8 @@ def test_day20() -> None:
 
     modules = get_modules(FILE_B)
     assert part1(modules) == 11687500
+
+
+def test_part2() -> None:
+    modules = get_modules(FILE_PROD)
+    assert part2(modules)[0] == 252667369442479