class_docstr: An abstract base class representing a corpus of words.
  Define the method _get_corpus in any derived class.
docstr: Retrieve an iterator over the words.
docstr_tok: ["Retrieve","an","iterator","over","the","words","."]
code: def __iter__(self) -> Iterator[str]:
      """Retrieve an iterator over the words."""
      return iter(self.words)
  
imports: from abc import ABC, abstractmethod
  from typing import Dict, Iterator, List, Tuple
  import nltk
label_desc: Use image node_id 9 for calling the Corpus obj's underlying member method code with example usage: obj.__iter__() and returns: iter