code: def _check_collections(self):
          
  
          self.collection_sizes = {}
          self.collection_total = 0
          for col in self.db.collection_names(include_system_collections=False):
              self.collection_sizes[col] = self.db.command('collstats', col).get(
                  'storageSize', 0)
              self.collection_total += self.collection_sizes[col]
  
          sorted_x = sorted(self.collection_sizes.items(),
                            key=operator.itemgetter(1))
  
          for item in sorted_x:
              self.log("Collection size (%s): %.2f MB" % (
                  item[0], item[1] / 1024.0 / 1024),
                       lvl=verbose)
  
          self.log("Total collection sizes: %.2f MB" % (self.collection_total /
                                                        1024.0 / 1024))
docs: Checks node local collection storage sizes