1 def get_first_int(values, key, default=0):
2     found = values.get(key, [''])
3     if found[0]:
4         found = int(found[0])
5     else:
6         found = default
7     return found

1 from urllib.parse import parse_qs
2 
3 my_values = parse_qs('red=5&blue=0&green=',
4                      keep_blank_values=True)
5 
6 print(repr(my_values))
7 
8 green = get_first_int(my_values, 'green');

 1 UNDEFINED = object()
 2 
 3 def divide_json(path):
 4     handle = open(path,'r+')            # May raise IOError
 5     try:
 6         data = handle.read()            # May raise UnicodeDecodeError
 7         op = json.loads(data)           # May raise ValueError
 8         value = (
 9             op['numerator']
10             op['denominator'])          # May raise ZeroDivisionError
11     except ZeroDivisionError as e:
12         return UNDEFINED
13     else:
14         op['result'] = value
15         result = json.dumps(op)
16         handle.seek(0)
17         handle.write(result)            # May raise IOError
18         return value
19     finally:
20         handle.close()