docstr: Move an existing element to the end.
  
  Raises KeyError if the element does not exist.
docstr_tok: ["Move","an","existing","element","to","the","end",".","Raises","KeyError","if","the","element","does","not","exist","."]
code: def move_to_end(self, key):
      """Move an existing element to the end.
  
      Raises KeyError if the element does not exist.
      """
      self[key] = self.pop(key)
  
imports: from collections import OrderedDict, Sequence
  from functools import wraps
  from itertools import compress
  from weakref import WeakKeyDictionary, ref
  from six.moves._thread import allocate_lock
  from toolz.sandbox import unzip
label_desc: Use image node_id 3 for calling the _WeakArgsOrderedDict obj's underlying member method code with example usage: obj.move_to_end(key) without return types