code: def _close_prepared_statement(self):
          
          self.prepared_sql = None
          self.flush_to_query_ready()
          self.connection.write(messages.Close('prepared_statement', self.prepared_name))
          self.connection.write(messages.Flush())
          self._message = self.connection.read_expected_message(messages.CloseComplete)
          self.connection.write(messages.Sync())
docs: Close the prepared statement on the server.