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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 merge(self, from_email, source_incidents):
 """Merge other incidents into this incident."""

        if from_email is None or not isinstance(from_email, six.string_types):
            raise MissingFromEmail(from_email)

        add_headers = {'from': from_email, }
        endpoint = '/'.join((self.endpoint, self.id, 'merge'))
        incident_ids = [entity['id'] if isinstance(entity, Entity) else entity
                        for entity in source_incidents]
        incident_references = [{'type': 'incident_reference', 'id': id_}
                               for id_ in incident_ids]

        return self.__class__.create(
            endpoint=endpoint,
            api_key=self.api_key,
            add_headers=add_headers,
            data_key='source_incidents',
            data=incident_references,
            method='PUT',
        )