Define a function CountBigWords(TFILE) in Python that counts and returns the total number of the words present in a text file TFILE which are more than 6 characters long. TFILE is the name of the text file, passed as an argument in the function.
If the test file TFILE contents are as follows:
I live in New Delhi
New Delhi is the national capital of India
The function CountBigWords() should return: 2