<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def default_chunksize(self):
 """ How much data will be processed at once, in case no chunksize has been provided. Notes ----- This variable respects your setting for maximum memory in pyemma.config.default_chunksize """

        if self._default_chunksize is None:
            try:
                # TODO: if dimension is not yet fixed (eg tica var cutoff, use dim of data_producer.
                self.dimension()
                self.output_type()
            except:
                self._default_chunksize = Iterable._FALLBACK_CHUNKSIZE
            else:
                self._default_chunksize = Iterable._compute_default_cs(self.dimension(),
                                                                       self.output_type().itemsize, self.logger)
        return self._default_chunksize