def getImportance(self, outName):
    """
      Method to extract the importance information of Fault Tree from SAPHIRE output files
      @ In, outName, string, the name of output file
      @ Out, headerNames, list, list of output variable names
      @ Out, outData, list, list of output variable values
    """
    headerNames = []
    outData = []
    outFile = os.path.abspath(os.path.expanduser(outName))
    data = np.loadtxt(outFile, dtype=object, delimiter=',', skiprows=2)
    headers = data[0]
    for i in range(1, len(data)):
      for j in range(1, len(headers)):
        name = _deweird(data[i,0]).strip().replace(" ", "~")
        header = _deweird(headers[j]).strip().replace(" ", "~")
        headerNames.append(name + '_' + header)
        outData.append(float(_deweird(data[i,j])))

    return headerNames, outData