def _dictlist_to_lists(dl, *keys):
    ''' convert a list of dictionaries to a dictionary of lists

    >>> dl = [{'a': 'test', 'b': 3}, {'a': 'zaz', 'b': 444},
              {'a': 'wow', 'b': 300}]
    >>> _dictlist_to_lists(dl)
    (['test', 'zaz', 'wow'], [3, 444, 300])
    '''
    lists = []
    for k in keys:
        lists.append([])
    for item in dl:
        for i, key in enumerate(keys):
            x = item[key]
            if isinstance(x, unicode):
                x = str(x)
            lists[i].append(x)
    return lists
convert a list of dictionaries to a dictionary of lists

    >>> dl = [{'a': 'test', 'b': 3}, {'a': 'zaz', 'b': 444},
              {'a': 'wow', 'b': 300}]
    >>> _dictlist_to_lists(dl)
    (['test', 'zaz', 'wow'], [3, 444, 300])