using a stuck and a dictionary of quotation_marks_dict = { "{': '}', '[': ']', '(': ')'}. inserting the chars as long it is opening quotation mark {/[/( . once we have closing quotation mark we compare it with the last quotation mark that was inserted to the stack, if it is not of the same type (comparing with key value in the quotation_marks_dict ) returning false, if we went trough all of the string and all matches and the stack is empty - return True.