Now I need to change it so that following expression are also not
allowed : NONE, N/A, =, !=, <, >, <=, and >=
Note that The symbols shouldn't be contained in any part of the data
provided as part of Comment_T.
Thus a string like SNONE or sN/Ass or s<dd are also invalid values.
I am not able to make out the appropriate regular experession which
would meet this requirement.
I will appreciate any suggestions regarding this.