I am trying to create a bunch of directories and sub directories at a specific location in my PC. My process is something like this:

1. Check if there's any directory with the same directory name. Skip if so.
2. If not, create the directory and the pre-defined sub directories under that directory.

This is the code I came up with using `os` module:

```
def Test():
    main_dir = ["FolderA", "FolderB"] 
    common_dir = ["SubFolder1", "SubFolder2", "SubFolder3"]

    for dir1 in main_dir:
        if not os.path.isdir(dir1):
            for dir2 in common_dir:
                os.makedirs("%s/%s" %(dir1,dir2))

```

I am wondering if there's any better way to do this very same task (probably shorter, more efficient and more pythonic)?