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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 _reaction_po_to_dict(tokens) -> Reaction: """Convert a reaction parse object to a DSL. :type tokens: ParseResult """

    return Reaction(
        reactants=_reaction_part_po_to_dict(tokens[REACTANTS]),
        products=_reaction_part_po_to_dict(tokens[PRODUCTS]),
    )