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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 changes_str(self):
        '''Returns a string describing the changes'''
        changes = ''
        for item in self._get_recursive_difference(type='intersect'):
            if item.diffs:
                changes = ''.join([changes,
                                   # Tabulate comment deeper, show the key attribute and the value
                                   # Next line should be tabulated even deeper,
                                   #  every change should be tabulated 1 deeper
                                   '\tidentified by {0} {1}:\n\t{2}\n'.format(
                                       self._key,
                                       item.past_dict[self._key],
                                       item.changes_str.replace('\n', '\n\t'))])
        for item in self._get_recursive_difference(type='removed'):
            if item.past_dict:
                changes = ''.join([changes,
                                   # Tabulate comment deeper, show the key attribute and the value
                                   '\tidentified by {0} {1}:'
                                   '\n\twill be removed\n'.format(self._key,
                                                                  item.past_dict[self._key])])
        for item in self._get_recursive_difference(type='added'):
            if item.current_dict:
                changes = ''.join([changes,
                                   # Tabulate comment deeper, show the key attribute and the value
                                   '\tidentified by {0} {1}:'
                                   '\n\twill be added\n'.format(self._key,
                                                                item.current_dict[self._key])])
        return changes