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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 parse_rst(text: str) -> docutils.nodes.document: """Parse text assuming it's an RST markup."""

    parser = docutils.parsers.rst.Parser()
    components = (docutils.parsers.rst.Parser,)
    settings = docutils.frontend.OptionParser(components=components).get_default_values()
    document = docutils.utils.new_document('<rst-doc>', settings=settings)
    parser.parse(text, document)
    return document