Convert set to list

[Larry Martell]

I feel like I've converted sets to lists before. But maybe not. Or
maybe I am losing it from having worked 70 hours this week.

Shouldn't this work?

(Pdb) print block['relative_chart1']['vessel_names']
set([u'Common Carotid', u'External Carotid', u'Internal Carotid'])
(Pdb) type(block['relative_chart1']['vessel_names'])
<type 'set'>
(Pdb) list(block['relative_chart1']['vessel_names'])
*** Error in argument: "(block['relative_chart1']['vessel_names'])"