code: def clear(self):
          
          for sample in self.metadata:
              try:
                  delattr(sample.depth, 'bases')
                  delattr(sample.depth, 'coverage')
                  delattr(sample.depth, 'length')
                  delattr(sample.depth, 'stddev')
              except AttributeError:
                  pass
docs: Clear out large attributes from the metadata objects