code: def book_name(self, number):
          '''Return name of book with given index.'''
          try:
              name = self.cur.execute("SELECT name FROM book WHERE number = ?;", [number]).fetchone()
          except:
              self.error("cannot look up name of book number %s" % number)
          return(str(name[0])f book_name(self, number):
          '''Return name of book with given index.'''
          try:
              name = self.cur.execute("SELECT name FROM book WHERE number = ?;", [number]).fetchone()
          except:
              self.error("cannot look up name of book number %s" % number)
          return(str(name[0]))
docs: Return name of book with given index.