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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 appendtextindex(table, index_or_dirname, indexname=None, merge=True, optimize=False):
 """ Load all rows from `table` into a Whoosh index, adding them to any existing data in the index. Keyword arguments: table A table container with the data to be loaded. index_or_dirname Either an instance of `whoosh.index.Index` or a string containing the directory path where the index is to be stored. indexname String containing the name of the index, if multiple indexes are stored in the same directory. merge Merge small segments during commit? optimize Merge all segments together? """

    import whoosh.index

    # deal with polymorphic argument
    if isinstance(index_or_dirname, string_types):
        dirname = index_or_dirname
        index = whoosh.index.open_dir(dirname, indexname=indexname,
                                      readonly=False)
        needs_closing = True
    elif isinstance(index_or_dirname, whoosh.index.Index):
        index = index_or_dirname
        needs_closing = False
    else:
        raise ArgumentError('expected string or index, found %r'
                            % index_or_dirname)

    writer = index.writer()
    try:

        for d in dicts(table):
            writer.add_document(**d)
        writer.commit(merge=merge, optimize=optimize)

    except Exception:
        writer.cancel()
        raise

    finally:
        if needs_closing:
            index.close()