code: def update_ngram(self, ngram, count):
          
          query = "UPDATE _{0}_gram SET count = {1}".format(len(ngram), count)
          query += self._build_where_clause(ngram)
          query += ";"
          self.execute_sql(query)
docs: Updates a given ngram in the database. The ngram has to be in the
          database, otherwise this method will stop with an error.
  
          Parameters
          ----------
          ngram : iterable of str
              A list, set or tuple of strings.
          count : int
              The count for the given n-gram.