<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def affiliation_history(self):
 """List of ScopusAffiliation objects representing former affiliations of the author. Only affiliations with more than one publication are considered. """

        aff_ids = [e.attrib.get('affiliation-id') for e in
                   self.xml.findall('author-profile/affiliation-history/affiliation')
                   if e is not None and len(list(e.find("ip-doc").iter())) > 1]
        return [ScopusAffiliation(aff_id) for aff_id in aff_ids]