docstr: prune out entries with lowest weight. 
docstr_tok: ["prune","out","entries","with","lowest","weight","."]
code: def _prunelowestweight(self):
      """prune out entries with lowest weight."""
      numentries = len(self._dict)
      if numentries >= self.maxentries:
          # evict according to entry's weight
          items = [
              (entry.weight, key) for key, entry in self._dict.items()
          ]
          items.sort()
          index = numentries - self.prunenum
          if index > 0:
              for weight, key in items[:index]:
                  # in MT situations the element might be gone
                  self.delentry(key, raising=False)
  
imports: from time import time
label_desc: Use image node_id 7 for calling the BasicCache obj's underlying member method code with example usage: obj._prunelowestweight() without return types