Parse the key currentcontrolset output.

def Parse(self, stat, unused_knowledge_base):
    """Parse the key currentcontrolset output."""
    value = stat.registry_data.GetValue()

    if not str(value).isdigit() or int(value) > 999 or int(value) < 0:
      raise parser.ParseError(
          "Invalid value for CurrentControlSet key %s" % value)
    yield rdfvalue.RDFString(
        "HKEY_LOCAL_MACHINE\\SYSTEM\\ControlSet%03d" % int(value))