Change methods not using its bound instance to staticmethods

ifpd2/probe.py

@@ -549,7 +549,8 @@ def reduce_probe_list(self, probe_list):
             print(e)
             raise
 
-    def select_probe_from_pair(self, probeA, probeB):
+    @staticmethod
+    def select_probe_from_pair(probeA, probeB):
         if probeA.size < probeB.size:
             return probeA
         else:

ifpd2/probe_set.py

@@ -183,7 +183,8 @@ def __init__(self, out_path):
             shutil.rmtree(out_path)
         os.mkdir(out_path)
 
-    def __build_probe_set_list(self, window_list, i):
+    @staticmethod
+    def __build_probe_set_list(window_list, i):
         probe_set_list = [(p,) for p in window_list[i]]
 
         for w in window_list[(i + 1) :]: