code: def _keep_positive(self):
          '''Internal method to strip elements with a negative or zero count'''
          nonpositive = [elem for elem, count in self.items() if not count > 0]
          for elem in nonpositive:
              del self[elem]
          return self _keep_positive(self):
          '''Internal method to strip elements with a negative or zero count'''
          nonpositive = [elem for elem, count in self.items() if not count > 0]
          for elem in nonpositive:
              del self[elem]
          return self
docs: Internal method to strip elements with a negative or zero count