docs: def __sum_stats(self, key, indice=None, mmm=None):
          """Return the sum of the stats value for the given key.
  
          * indice: If indice is set, get the p[key][indice]
          * mmm: display min, max, mean or current (if mmm=None)
          """
          # Compute stats summary
          ret = 0
          for p in self.stats:
              if key not in p:
                  # Correct issue #1188
                  continue
              if p[key] is None:
                  # Correct https://github.com/nicolargo/glances/issues/1105#issuecomment-363553788
                  continue
              if indice is None:
                  ret += p[key]
              else:
                  ret += p[key][indice]
  
          # Manage Min/Max/Mean
          mmm_key = self.__mmm_key(key, indice)
          if mmm == 'min':
              try:
                  if self.mmm_min[mmm_key] > ret:
                      self.mmm_min[mmm_key] = ret
              except AttributeError:
                  self.mmm_min = {}
                  return 0
              except KeyError:
                  self.mmm_min[mmm_key] = ret
              ret = self.mmm_min[mmm_key]
          elif mmm == 'max':
              try:
                  if self.mmm_max[mmm_key] < ret:
                      self.mmm_max[mmm_key] = ret
              except AttributeError:
                  self.mmm_max = {}
                  return 0
              except KeyError:
                  self.mmm_max[mmm_key] = ret
              ret = self.mmm_max[mmm_key]
  
          return ret