In this section you will apply changes to values, how to define your own simple functions.

We will also introduce the following functions for the first time:

atom	create an anonymous function, one without a name
deref, @	assign a name to a function

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(def mutants (atom []))

(defn add-mutant [mutant]
  (swap! mutants conj mutant))

(add-mutant "Black Widow")