edited level remover to private variables

lvlspy/species.py

@@ -72,20 +72,15 @@ def remove_level(self, level):
             On successful return, the level and all connected transitions have been removed.
 
         """
-        upper_conn = self.get_upper_linked_levels(level)
-        lower_conn = self.get_lower_linked_levels(level)
-
-        for l in upper_conn:
-            t = self.get_level_to_level_transition(l,level)
-            if t is None:
-                continue
-            self.remove_transition(t)
+        for _l in self.get_upper_linked_levels(level):
+            _t = self.get_level_to_level_transition(_l,level)
+            if _t:
+                self.remove_transition(t)
 
-        for l in lower_conn:
-            t = self.get_level_to_level_transition(level,l)
-            if t is None:
-                continue
-            self.remove_transition(t)
+        for _l in self.get_lower_linked_levels(level):
+            _t = self.get_level_to_level_transition(level,_l)
+            if _t:
+                self.remove_transition(t)
 
         self.levels.remove(level)