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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 DropPrivileges():
 """Attempt to drop privileges if required."""

  if config.CONFIG["Server.username"]:
    try:
      os.setuid(pwd.getpwnam(config.CONFIG["Server.username"]).pw_uid)
    except (KeyError, OSError):
      logging.exception("Unable to switch to user %s",
                        config.CONFIG["Server.username"])
      raise