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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 calculating_node_creator(self, classes_by_source, runtime_classpath, product_deps_by_src, target_to_vts):
 """Strategy directly computes dependency graph node based on `classes_by_source`, `runtime_classpath`, `product_deps_by_src` parameters and stores the result to the build cache. """

    analyzer = JvmDependencyAnalyzer(get_buildroot(), runtime_classpath)
    targets = self.context.targets()
    targets_by_file = analyzer.targets_by_file(targets)
    transitive_deps_by_target = analyzer.compute_transitive_deps_by_target(targets)
    def creator(target):
      transitive_deps = set(transitive_deps_by_target.get(target))
      node = self.create_dep_usage_node(target,
                                        analyzer,
                                        product_deps_by_src,
                                        classes_by_source,
                                        targets_by_file,
                                        transitive_deps)
      vt = target_to_vts[target]
      mode = 'w' if PY3 else 'wb'
      with open(self.nodes_json(vt.results_dir), mode=mode) as fp:
        json.dump(node.to_cacheable_dict(), fp, indent=2, sort_keys=True)
      vt.update()
      return node

    return creator