class_docstr: Set the remembers the order elements were added
class_docstr_tok: ["Set","the","remembers","the","order","elements","were","added"]
code: def __contains__(self, key):
      return key in self.__map
  
imports: from __future__ import absolute_import, print_function, division
  import types
  import weakref
  from six import string_types
label_desc: Use image node_id 4 for calling the OrderedSet obj's underlying member method code with example usage: obj.__contains__(key) and returns: unknown