code: def truncate_schema(self):
          
  
          assert self.server == 'localhost'
          con = self.connection or self._connect()
          self._initialize(con)
          cur = con.cursor()
  
          cur.execute('DELETE FROM publication;')
          cur.execute('TRUNCATE systems CASCADE;')
  
          con.commit()
          con.close()
  
          return
docs: Will delete all data in schema. Only for test use!