code: public static <A, B, C> Choice3<A, B, C> a(A a) {
          return new _A<>(a);
      }
docs: Static factory method for wrapping a value of type <code>A</code> in a {@link Choice3}.
  
  @param a   the value
  @param <A> the first possible type
  @param <B> the second possible type
  @param <C> the third possible type
  @return the wrapped value as a {@link Choice3}&lt;A, B, C&gt;