public override void OnImportAsset(AssetImportContext ctx)
{
var existedPythonScriptAsset = UnityEditor.AssetDatabase.LoadMainAssetAtPath(ctx.assetPath) as PythonScript;
//script text
var text = File.ReadAllText(ctx.assetPath);
int updateCount = existedPythonScriptAsset == null ? 0 : existedPythonScriptAsset.updateCount;
var pythonScriptAsset = PythonScript.CreateFromString(text, updateCount);
//script name
var fileName = Path.GetFileNameWithoutExtension(ctx.assetPath);
pythonScriptAsset.name = fileName;
//script asset
#if UNITY_2017_3_OR_NEWER
ctx.AddObjectToAsset("script", pythonScriptAsset);
ctx.SetMainObject(pythonScriptAsset);
#else
ctx.SetMainAsset("script", pythonScriptAsset);
#endif
}