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In this project, we'll use step-by-step refactoring to vastly improve the readability and structure of a program.

The Refactor Factory

Great work! This code looks better already.

We can remove even more, however. There's one `return` statement in this code that we can change from explicit to implicit!

Recall that Ruby will automatically return the value of the last expression it evaluates.

Less is More

One of the most common suggestions when it comes to writing is to omit needless words, and it applies just as much to writing Ruby as writing stories.

There are two control structures to change here:

1. The `unless` block:
```ruby
  unless n.is_a? Integer
    return "n must be an integer."
  end
```

2. The `if` block below the `unless` block:
```ruby
  if n <= 0
    return "n must be greater than 0."
  end
```

Both blocks can be simplified using the zen of Ruby! 

Omit Needless Words

Fantastic! You really improved that code, and all it took was a little Ruby know-how.

Nice work!

We're going to reinforce our knowledge of Ruby best practices by refactoring some existing code. As mentioned, **refactoring** is the process by which we improve a code's structure, appearance, and/or performance without modifying its overall behavior.

The code in the editor is a Ruby method, `first_n_primes`, that takes a number *n* and generates a list of the first *n* prime numbers. Unfortunately, our poor author hasn't yet mastered all the tools available in Ruby. But we can fix that!