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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_table_cells(table):
 """Helper function with caching for table cells and the cells' sentences. This function significantly improves the speed of `get_row_ngrams` primarily by reducing the number of queries that are made (which were previously the bottleneck. Rather than taking a single mention, then its sentence, then its table, then all the cells in the table, then all the sentences in each cell, and performing operations on that series of queries, this performs a single query for all the sentences in a table and returns all of the cells and the cells sentences directly. :param table: the Table object to cache. """

    sent_map = defaultdict(list)
    for sent in table.sentences:
        if sent.is_tabular():
            sent_map[sent.cell].append(sent)
    return sent_map