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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 create(cls, env, filenames, trim=False):
 """Create and return a final graph. Args: env: An environment.Environment object filenames: A list of filenames trim: Whether to trim the dependencies of builtin and system files. Returns: An immutable ImportGraph with the recursive dependencies of all the files in filenames """

        import_graph = cls(env)
        for filename in filenames:
            import_graph.add_file_recursive(os.path.abspath(filename), trim)
        import_graph.build()
        return import_graph