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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 sequence_to_string( a_list, open_bracket_char='[', close_bracket_char=']', delimiter=", " ):
 """a dedicated function that turns a list into a comma delimited string of items converted. This method will flatten nested lists."""

    return "%s%s%s" % (
        open_bracket_char,
        delimiter.join(
            local_to_str(x)
            for x in a_list
        ),
        close_bracket_char
    )