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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 _strip_key(dictionary, keyword):
    '''
    look for a certain key within a dictionary and nullify ti's contents, check within nested
    dictionaries and lists as well.  Certain attributes such as "generation" will change even
    when there were no changes made to the entity.
    '''

    for key, value in six.iteritems(dictionary):
        if key == keyword:
            dictionary[key] = None
        elif isinstance(value, dict):
            _strip_key(value, keyword)
        elif isinstance(value, list):
            for item in value:
                if isinstance(item, dict):
                    _strip_key(item, keyword)

    return dictionary