Index: helpers.py
==================================================================
--- helpers.py
+++ helpers.py
@@ -45,20 +45,20 @@
         if bCreatePath and not os.path.exists(spDest):
             os.makedirs(spDest, exist_ok=True)
         print("> unzip in: "+ spDest)
         spInstall = os.path.abspath(spDest)
         if os.path.isdir(spInstall):
-            eraseFolder(spInstall)
+            eraseFolderContent(spInstall)
             with zipfile.ZipFile(spfZip) as hZip:
                 hZip.extractall(spDest)
         else:
             print("# folder <" + spDest + "> not found")
     else:
         print("path destination is empty")
 
 
-def eraseFolder (sp):
+def eraseFolderContent (sp):
     "erase content of a folder"
     for sf in os.listdir(sp):
         spf = os.path.join(sp, sf)
         try:
             if os.path.isfile(spf):
@@ -72,11 +72,11 @@
 def createCleanFolder (sp):
     "make an empty folder or erase its content if not empty"
     if not os.path.exists(sp):
         os.makedirs(sp, exist_ok=True)
     else:
-        eraseFolder(sp)
+        eraseFolderContent(sp)
 
 
 def copyFolder (spSrc, spDst):
     "copy folder content from src to dst"
     try:

ADDED   purge.py
Index: purge.py
==================================================================
--- purge.py
+++ purge.py
@@ -0,0 +1,46 @@
+# Python
+
+import os
+import argparse
+import sys
+import shutil
+
+import helpers
+
+
+def getFolders (sp):
+    for sf in os.listdir(sp):
+        if os.path.isdir(sp+"/"+sf):
+            yield from getFolders(sp+"/"+sf)
+            yield (sf, sp+"/"+sf)
+
+
+def purge (sFolderName, bDeleteContentOnly):
+    for sf, sp in getFolders("."):
+        if sf == sFolderName:
+            if bDeleteContentOnly:
+                helpers.eraseFolderContent(sp)
+                print(sp, "[content deleted]")
+            else:
+                shutil.rmtree(sp)
+                print(sp, "[erased]")
+
+
+def main ():
+    "purge cruft and other files"
+    print("Python: " + sys.version)
+    if sys.version < "3.7":
+        print("Python 3.7+ required")
+        return
+
+    xParser = argparse.ArgumentParser()
+    xParser.add_argument("-b", "--build", help="purge _build", action="store_true")
+    xArgs = xParser.parse_args()
+
+    purge("__pycache__", False)
+    if xArgs.build:
+        purge("_build", True)
+
+
+if __name__ == '__main__':
+    main()