[Answer]-Coercing to Unicode: need string or buffer, list found

string.replace() uses strings as parameters not lists.
request_accts
Is a list.

I’m not a django expert but maybe this will work:

trgmst_info = request.DATA['trgmst_info'][0]
request_accts = ['request-dev', 'request-qa', 'request-uat', 'request-prod']
for rep in request_accts:
    request.DATA['trgmst_info'] = [rd.replace(rep, settings.REQUEST_ACCT) for rd in request.DATA['trgmst_info']]