def _make_summary_statistic(attr):
def _fn(self):<EOL><INDENT>if any(self._dist_fn_args):  <EOL><INDENT>raise ValueError(<EOL>'<STR_LIT>' + attr + '<STR_LIT>'<EOL>'<STR_LIT>'.format(self.model))<EOL><DEDENT>return self._unflatten(getattr(d(), attr)() for d in self._dist_fn_wrapped)  <EOL><DEDENT>return _fn<EOL>
Factory for making summary statistics, eg, mean, mode, stddev.