Say you have a list of country names and you want to highlight those countries on a map, shaded by the number of repitions of that country in the list. You might want to go from a list like this:

locations = ['Slovenia',
         'Slovenia',
         'Italy',
         'Russian Federation',
         'Serbia',
         'United Kingdom',
         'Germany',
         'Norway',
         'Peru',
         'Poland',
         'Moldova',
         ...
         'Germany',
         'France',
         'United Kingdom']

To an image like this, from google charts:

The google charts API requires ISO 3166 country codes, pycountry can translate country names to ISO 3166 codes:

codes = [pycountry.countries.get(name=l).alpha2 for l in locations]

Counting the repitions in codes is easy:

code_count = defaultdict(int)
for code in codes:
    code_count[code] += 1

The last thing to do is save the parameters and make the charts URL:

base = 'http://chart.apis.google.com/chart?'
params = {
    'chco': 'FFFFFF,CCFFCC,88FF88,00FF00',
    'chf': 'bg,s,EAF7FE',
    'chs': '440x220',
    'cht': 't',
    'chtm': 'world'}

params['chd'] = 't:'+
                ",".join(
                str(int((counts[k]/float(max(counts.values()))*100))) 
                for k in sorted(counts.keys()))

params['chld'] = "".join(sorted(counts.keys()))

URL = base + "&".join(
            "=".join([k, params[k]) for k in params.keys())

After all that URL looks like:

http://chart.apis.google.com/chart?chd=t:60,20,20,100,40,100,60,20,20,20,20,20,20,100,20,60,60&chf=bg,s,EAF7FE&chco=FFFFFF,CCFFCC,88FF88,00FF00&chtm=world&chld=BEBYCZDEFRGBITMDNOPEPLPTRSRUSESIUA&chs=440x220&cht=t

Which is the link to the map shown above.