Before you do anything first recognize what it is you wish to do…
Once you identify that these should help get you there:
‘list the installed modules’
frappe@erpnext:~/frappe-bench$ sudo pip list
frappe@erpnext:~/frappe-bench$ sudo pip install dropbox_backup
frappe@erpnext:~/frappe-bench$ sudo pip list | grep dropbox-backup
dropbox-backup (0.1.6)
In my case Dropbox Settings is not set and the module was not installed.
I also found this ImportError: No module named bleach