Finds texts whose translation depends on context.

        Example.
          Here the word "Palacio" is translated from Spanish to English in
          multiple ways. Feed language is es (Spanish).

          trans_id,lang,translation
          stop-name-1,es,Palacio
          stop-name-1,en,Palace
          headsign-1,es,Palacio
          headsign-1,en,To Palace

def _find_context_dependent_names(self):
        """Finds texts whose translation depends on context.

        Example.
          Here the word "Palacio" is translated from Spanish to English in
          multiple ways. Feed language is es (Spanish).

          trans_id,lang,translation
          stop-name-1,es,Palacio
          stop-name-1,en,Palace
          headsign-1,es,Palacio
          headsign-1,en,To Palace
        """
        n_occurences_of_original = {}
        for trans_id, translations in self.translations_map.items():
            try:
                original_name = translations[self.feed_language]
            except KeyError:
                raise Exception(
                    'No translation in feed language for %s, available: %s' %
                    (trans_id, translations))
            n_occurences_of_original[original_name] = (
                n_occurences_of_original.get(original_name, 0) +
                1)

        self.context_dependent_names = set(
            name
            for name, occur in n_occurences_of_original.items()
            if occur > 1)
        print('Total context-dependent translations: %d' %
              len(self.context_dependent_names))