Import slicer module in script cli module

Development
1

I create a script cli module and call this script as below：

PythonQt::init();
PythonQtObjectPtr context = PythonQt::self()->getMainModule();

QString cmd = QString(
    "import os\n"
    "import sys\n"
    "CTASegExePath=slicer.app.slicerHome + '/CTAModule/lib/VesselCenterline.py'\n"
    "pythonSlicerExecutablePath=os.path.dirname(sys.executable)+'/PythonSlicer.exe'\n"
    "commandLine = [pythonSlicerExecutablePath, CTASegExePath]\n"
    "proc=slicer.util.launchConsoleProcess( commandLine ,useStartupEnvironment=True)\n"
    "slicer.util.logProcessOutput(proc)\n"
);  
context.evalScript(cmd);

in VesselCenterline.py scirpt

I cant import slicer module and call slicer python API, it says no module named “xxx”

How can i do about this ?