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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_branchinglevel(self, branchinglevel_node, depth, validate):
 """ Parse one branching level. :param branchinglevel_node: ``etree.Element`` object with tag "logicTreeBranchingLevel". :param depth: The sequential number of this branching level, based on 0. :param validate: Whether or not the branching level, its branchsets and their branches should be validated. Enumerates children branchsets and call :meth:`parse_branchset`, :meth:`validate_branchset`, :meth:`parse_branches` and finally :meth:`apply_branchset` for each. Keeps track of "open ends" -- the set of branches that don't have any child branchset on this step of execution. After processing of every branching level only those branches that are listed in it can have child branchsets (if there is one on the next level). """

        new_open_ends = set()
        branchsets = branchinglevel_node.nodes
        for number, branchset_node in enumerate(branchsets):
            branchset = self.parse_branchset(branchset_node, depth, number,
                                             validate)
            self.parse_branches(branchset_node, branchset, validate)
            if self.root_branchset is None:  # not set yet
                self.num_paths = 1
                self.root_branchset = branchset
            else:
                self.apply_branchset(branchset_node, branchset)
            for branch in branchset.branches:
                new_open_ends.add(branch)
            self.num_paths *= len(branchset.branches)
        if number > 0:
            logging.warning('There is a branching level with multiple '
                            'branchsets in %s', self.filename)
        self.open_ends.clear()
        self.open_ends.update(new_open_ends)