Given a phrase, count the occurrences of each word in that phrase.
For example for the input "olly olly in come free"
olly: 2
in: 1
come: 1
free: 1
If you don't know how to run Vader tests, see: Tests.
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This is a classic toy problem, but we were reminded of it by seeing it in the Go Tour.
It's possible to submit an incomplete solution so you can see how others have completed the exercise.