Fix race with parallel mkdir_silent and nested folders

src/ifstools/utils.py

@@ -1,21 +1,8 @@
-import errno
 import os
 
+
 def mkdir_silent(dir):
-    try: # python 3
-        FileExistsError
-        try:
-            os.mkdir(dir)
-        except FileExistsError:
-            pass
-    except NameError: # python 2
-        try:
-            os.mkdir(dir)
-        except OSError as e:
-            if e.errno == errno.EEXIST:
-                pass
-            else:
-                raise
+    os.makedirs(dir, exist_ok=True)
 
 def save_with_timestamp(filename, data, timestamp):
     mkdir_silent(os.path.dirname(filename))