code: def swap(self, core, other):
          
          params = {
              'action': 'SWAP',
              'core': core,
              'other': other,
          }
          return self._get_url(self.url, params=params)
docs: http://wiki.apache.org/solr/CoreAdmin#head-928b872300f1b66748c85cebb12a59bb574e501b