A little help with copying data from a parent to a child table

I have created a custom doctype “Fistula Outreach Visits” which has a child table of “Fistula Enquiries”. I wish to copy some location data from FOV to FE. From other posts I learned this script might work for the field named region:

frappe.ui.form.on(“Fistula Outreach Visits”,“refresh”, function(){
for (var i =0; i < cur_frm.doc.fistula_enqiries.length; i++){
cur_frm.fistula_enqiries[i].region = cur_frm.doc.region

which I have associated with the FOV doctype. NB fistula_enqiries (the mispelling is real) is the field name of the child table.

Sadly when I refresh an FOV form I get a syntax error as follows:
SyntaxError: Invalid or unexpected token
at Class.setup (http://kivulini-2:8080/assets/js/form.min.js?ver=1520836772.39:2648:18)
at _f.Frm.setup (http://kivulini-2:8080/assets/js/form.min.js?ver=1520836772.39:172:22)
at _f.Frm.refresh (http://kivulini-2:8080/assets/js/form.min.js?ver=1520836772.39:446:9)
at Class.load (http://kivulini-2:8080/assets/js/form.min.js?ver=1520836772.39:87:33)
at http://kivulini-2:8080/assets/js/form.min.js?ver=1520836772.39:82:7
at Object.callback (http://kivulini-2:8080/assets/js/desk.min.js?ver=1520836772.39:5516:6)
at Object.callback [as success_callback] (http://kivulini-2:8080/assets/js/desk.min.js?ver=1520836772.39:1437:16)
at _ (http://kivulini-2:8080/assets/js/desk.min.js?ver=1520836772.39:1461:34)
at Object. (http://kivulini-2:8080/assets/js/desk.min.js?ver=1520836772.39:1562:5)
at i (http://kivulini-2:8080/assets/frappe/js/lib/jquery/jquery.min.js:2:27151)

Can anyone advise where I have gone wrong?