How to write a code to open and read text file by clicking on the "text file"

[kavindu]

Thank you Dead_Eye. I wrote a code just as he said and I selected my python script as the default for txt files.
this is my python code

import sys
file=open(sys.argv[1],"r")
print(file.read())

When I dragged a txt file and dropped it over my python script, the python script reads the text file successfully. But when I double clicked on the txt file, then it shows following error msg

Error:
C:Users\Kavindu\Documents\python_workspace\a2.txt is not a valid Win32 application

What is the reason for this error msg, and how to solve this problem. I need to open txt files with my python script by clicking on text files

plz can someone help me with this