code: def fit(self, corpus, window=10, ignore_missing=False):
          
  
          self.matrix = construct_cooccurrence_matrix(corpus,
                                                      self.dictionary,
                                                      int(self.dictionary_supplied),
                                                      int(window),
                                                      int(ignore_missing))
docs: Perform a pass through the corpus to construct
          the cooccurrence matrix.
  
          Parameters:
          - iterable of lists of strings corpus
          - int window: the length of the (symmetric)
            context window used for cooccurrence.
          - bool ignore_missing: whether to ignore words missing from
                                 the dictionary (if it was supplied).
                                 Context window distances will be preserved
                                 even if out-of-vocabulary words are
                                 ignored.
                                 If False, a KeyError is raised.