The palindrome checker task involves determining whether a given string is a palindrome or not. A palindrome is a sequence of characters that reads the same forwards and backward, ignoring spaces, punctuation, and capitalization.
For example, the following words are palindromes: level, radar, and madam.

We can use stack to solve this task effectively!.
By pushing characters onto the stack in the order they appear in the string, we can then pop characters off the stack and compare them with those from the string. This approach allows us to simultaneously compare characters from both ends of the string, making it an effective way to check for palindromes.

Your task is to fill in all gaps in is_palindrome().