Most languages are case-sensitive, so keywords can only be written with the rules of the keyword (case-sensitive), and the Regular Expression (RE) which describes the lexemen is very simple

Solution: A Regular Expression is nothing but an efficient way to implement logic. With the help of regular expressions, the implementation of logic is reduced by a very large size. For instance, if implementation takes around four to five lines of code in a function, the same logic can be implemented using the regular expressions in one line of code. Code for a regular expression to accept keywords without concerning about their case-sensitiveness is implemented using the Python programming language and is provided down below, please find attached the code and the screenshot for the same.

Code:

import re
print (re.search('timbaktoo', 'TimBAkToO', re.IGNORECASE))
print (re.match('timbaktoo', 'TIMbaktOo', re.IGNORECASE))

PFA