Return Words Present in Exactly One Message

## Return Words Present in Exactly One Message Implement `unique_string(msg1, msg2)`. Given two message strings, return a list of words that appear in exactly one message: the symmetric difference of the messages' word sets. Repeated occurrences of a word within one message do not produce repeated words in the result. A word found in both messages is excluded. The exercise does not prescribe the order of the returned list, so different permutations of the same words are valid. ### Clarifications Agree on what counts as a word and whether comparison is case-sensitive before implementing. The prompt does not supply punctuation, tokenization, or case-normalization rules. Apply the agreed convention consistently to both messages. ```hint Consider membership before frequency The requested distinction depends on which messages contain a word. ``` ### What a Strong Answer Covers - Represents each message's distinct words under the same tokenization and case convention. - Includes words belonging to only one message and excludes words shared by both. - Handles repeated words, identical messages, and an empty message. - Returns each qualifying word once and recognizes that result ordering is unrestricted. ### Follow-up Questions - What happens when the two messages contain the same word several times each? - Which tokenization and case rules would you clarify for punctuation or mixed-case text?