How to use the icontract._recompute.Visitor function in icontract

assert len(closure_cells) == len(freevars), \
                "Number of closure cells of a condition function ({}) == number of free vars ({})".format(
                    len(closure_cells), len(freevars))

            for cell, freevar in zip(closure_cells, freevars):
                closure_dict[freevar] = cell.cell_contents

        variable_lookup.append(closure_dict)

        # Add globals to the lookup
        if condition.__globals__ is not None:  # type: ignore
            variable_lookup.append(condition.__globals__)  # type: ignore

        # pylint: disable=protected-access
        recompute_visitor = icontract._recompute.Visitor(variable_lookup=variable_lookup)

        recompute_visitor.visit(node=lambda_inspection.node.body)
        recomputed_values = recompute_visitor.recomputed_values

        repr_visitor = Visitor(
            recomputed_values=recomputed_values, variable_lookup=variable_lookup, atok=lambda_inspection.atok)
        repr_visitor.visit(node=lambda_inspection.node.body)

        reprs = repr_visitor.reprs
    else:
        for key, val in condition_kwargs.items():
            if _representable(value=val):
                reprs[key] = val

    parts = []  # type: List[str]
    for key in sorted(reprs.keys()):