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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 _add_rg(unmapped_file, config, names):
 """Add the missing RG header."""

    picard = broad.runner_from_path("picard", config)
    rg_fixed = picard.run_fn("picard_fix_rgs", unmapped_file, names)
    return rg_fixed