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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def add_enumerable_item_to_dict(dict_, key, item):
 """Add an item to a list contained in a dict. For example: If the dict is ``{'some_key': ['an_item']}``, then calling this function will alter the dict to ``{'some_key': ['an_item', 'another_item']}``. If the key doesn't exist yet, the function initializes it with a list containing the item. List-like items are allowed. In this case, the existing list will be extended. Args: dict_ (dict):
 the dict to modify key (str):
 the key to add the item to item (whatever):
 The item to add to the list associated to the key """

    dict_.setdefault(key, [])
    if isinstance(item, (list, tuple)):
        dict_[key].extend(item)
    else:
        dict_[key].append(item)