Answer:
This is because the key in relationships['jimmy'] is wrong. The first letter "j" should be uppercase. The key in the given dictionary is "Jimmy" and therefore a lowercase "j" will result in a KeyError exception. The key is case sensitive and therefore a minor mistake in a single letter either in lowercase or uppercase will cause the error. The correct usage of key to address the value should be relationships["Jimmy"].
Answer:
Sound
Explanation:
Dart is object oriented. It's sound feature helps to make codes more maintainable and readable. The sound type system means that one can never experience w state where where an expression would evaluate to a value that wouldn't match that expressions static type.
The sound system makes the code to be unambiguous. It makes the code to be easier to read as types cannot lie, also your code would be more maintainable since when a piece of code gets to be changed, you would be warned of other pieces that may have gotten broken.
