Fixed smaller typing issues and moved traverse test

b_asic/traverse_tree.py

@@ -8,7 +8,7 @@ TODO:
     - When we no more out ports can be traversed return results and end.
 """
 
-from typing import List
+from typing import List, Optional
 from collections import deque
 
 from b_asic.operation import Operation
@@ -39,16 +39,16 @@ class Traverse:
 
         return visited
 
-    def traverse(self, _type: Operation = None) -> List[Operation]:
+    def traverse(self, type_: Optional[Operation] = None) -> List[Operation]:
         """Traverse the the operation tree and return operation where type matches.
         If the type is None then return the entire tree.
 
         Keyword arguments:
-        _type -- the operation type to search for (default None)
+        type_-- the operation type to search for (default None)
         """
 
         operations: List[Operation] = self._breadth_first_search(self._initial_operation)
-        if _type is not None:
-            operations = [oper for oper in operations if isinstance(oper, _type)]
+        if type_ is not None:
+            operations = [oper for oper in operations if isinstance(oper, type_)]
 
         return operations