[python] 'too many values to unpack', iterating over a dict. key=>string, value=>list

Python 2

You need to use something like iteritems.

for field, possible_values in fields.iteritems():
    print field, possible_values

See this answer for more information on iterating through dictionaries, such as using items(), across python versions.

Python 3

Since Python 3 iteritems() is no longer supported. Use items() instead.

for field, possible_values in fields.items():
    print(field, possible_values)