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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 calculate_etag(file_path):
 """ Calculate an etag value Args: a_file (pathlib.Path):
 The filepath to the Returns: String of the etag value to be sent back in header """

        stat = file_path.stat()
        etag = "%x-%x" % (stat.st_mtime_ns, stat.st_size)
        return etag