code: def discard(self, key):
      if key in self.map:
          key, prev, next = self.map.pop(key)
          prev[NEXT] = next
          next[PREV] = prev
  
file_path: nibabel/nibabel/externals/oset.py
imports: from collections.abc import MutableSet
label_desc: Use image node_id 6 for calling the OrderedSet obj's underlying member method code with example usage: obj.discard(key) without return types