This method is used to check whether a string, array, or other data structure is empty or contains only whitespace characters.
 It returns true if the object is empty contains only whitespace, or is nil. Otherwise, it returns false. 

Example:

"".blank? # true (empty string) 
" ".blank? # true (whitespace characters only) 
nil.blank? # true (nil) 
"hello".blank? # false (contains non-whitespace characters) 
[1, 2, 3].blank? # false (array with elements)