<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _CheckInstallSuccess(self):
 """Checks if the installer installed correctly."""

    if not os.path.exists(self.install_path):
      raise RuntimeError("Install failed, no files at: %s" % self.install_path)

    try:
      output = subprocess.check_output(["sc", "query", self.service_name])
      service_running = "RUNNING" in output
    except subprocess.CalledProcessError as e:
      if e.returncode == 1060:
        # 1060 means: The specified service does not exist as an installed
        # service.
        service_running = False
      else:
        raise

    if self.expect_service_running:
      if not service_running:
        raise RuntimeError(
            "GRR service not running after install, sc query output: %s" %
            output)
    else:
      if service_running:
        raise RuntimeError(
            "GRR service running after install with expect_service_running == "
            "False, sc query output: %s" % output)