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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 refresh(self):
        '''
        Refresh the contents of the ``_updates`` collection. This gets all
        updates in the Windows Update system and loads them into the collection.
        This is the part that is slow.

        Code Example:

        .. code-block:: python

            import salt.utils.win_update
            wua = salt.utils.win_update.WindowsUpdateAgent()
            wua.refresh()
        '''
        # https://msdn.microsoft.com/en-us/library/windows/desktop/aa386526(v=vs.85).aspx
        search_string = 'Type=\'Software\' or ' \
                        'Type=\'Driver\''

        # Create searcher object
        searcher = self._session.CreateUpdateSearcher()
        self._session.ClientApplicationID = 'Salt: Load Updates'

        # Load all updates into the updates collection
        try:
            results = searcher.Search(search_string)
            if results.Updates.Count == 0:
                log.debug('No Updates found for:\n\t\t%s', search_string)
                return 'No Updates found: {0}'.format(search_string)
        except pywintypes.com_error as error:
            # Something happened, raise an error
            hr, msg, exc, arg = error.args  # pylint: disable=W0633
            try:
                failure_code = self.fail_codes[exc[5]]
            except KeyError:
                failure_code = 'Unknown Failure: {0}'.format(error)

            log.error('Search Failed: %s\n\t\t%s', failure_code, search_string)
            raise CommandExecutionError(failure_code)

        self._updates = results.Updates