Python dictionary doesn't allow key to be repeated. However, we can use defaultdict to find a workaround. This class is defined in collections module.
Use list as default factory for defaultdict object
>>> from collections import defaultdict >>> d=defaultdict(list)
Here is a list of tuples each with two items. First item is found to be repeatedly used. This list is converted in defaultdict
>>> for k,v in l: d[k].append(v)
Convert this defaultdict in a dictionary object using dict() function
>>> dict(d)
{1: [111, 'aaa'], 2: [222, 'bbb'], 3: [333, 'ccc']}
