How to run python executable (dummy.exe) file from c# application

How to run an executable python file ( dummy.exe) from c# application? I can run the .py file using similar code like following

 private void run_cmd(string cmd, string args)
 ProcessStartInfo start = new ProcessStartInfo();
 start.FileName = cmd;//cmd is full path to python.exe
 start.Arguments = args;//args is path to .py file and any cmd line args
 start.UseShellExecute = false;
 start.RedirectStandardOutput = true;
 using(Process process = Process.Start(start))
     using(StreamReader reader = process.StandardOutput)
         string result = reader.ReadToEnd();

But not able to execute .exe file when i tried to give the filename as path to dummy.exe. I have only single file (dummy.exe). I am not using IronPython(and would not prefer unless this is only way)

Edit:- I do not have .py file, i have only python executable (dummy.exe) file. Other answers are about giving .py file as an argument to python.exe