diff --git a/npm_install.py b/npm_install.py
index 089a9ed..d51a8da 100644
--- a/npm_install.py
+++ b/npm_install.py
@@ -7,7 +7,7 @@ def npm_create_package_lock_file(package):
     
     
 def get_all_urls_packages():
-    return findall("https://.+.tgz", open("package-lock.json", "rt").read())
+    return list(dict.fromkeys(findall("https://.+.tgz", open("package-lock.json", "rt").read())))