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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 post_versions_list(self, updater_name=None, updater_id=None, post_id=None, start_id=None):
 """Get list of post versions. Parameters: updater_name (str):
 updater_id (int):
 post_id (int):
 start_id (int):
 """

        params = {
            'search[updater_name]': updater_name,
            'search[updater_id]': updater_id,
            'search[post_id]': post_id,
            'search[start_id]': start_id
            }
        return self._get('post_versions.json', params)