code: def counter_from_corpus(self, corpus):
          
          assert corpus in ['phi5', 'tlg'], \
              "Corpus '{0}' not available. Choose from 'phi5' or 'tlg'.".format(corpus)
  
          all_strings = self._assemble_corpus_string(corpus=corpus)
          return self.counter_from_str(all_strings)
docs: Build word frequency list from one of several available corpora.
          TODO: Make this count iteratively, not all at once