title: Why does the test_default_value_is_the_same_object in about_hashes.rb of Ruby Koans exercises have the answer of an array?
body: <p>I'm doing the ruby koans exercises and am a bit confused about why the answers are such in the  test_default_value_is_the_same_object method exercises. Below is the code:</p>
  
  <pre><code>def test_default_value_is_the_same_object
  hash = Hash.new([])
  
  hash[:one] &lt;&lt; "uno"
  hash[:two] &lt;&lt; "dos"
  
  assert_equal ["uno", "dos"], hash[:one]
  assert_equal ["uno", "dos"], hash[:two]
  assert_equal ["uno", "dos"], hash[:three]
  end
  </code></pre>
  
  <p>I'm not sure why no matter what the key is, the value is always "uno" and "dos"? I thought when the key is <code>one</code>, the returned value should be "uno"; when key is "two", the returned value should be "dos". Why no matter what the keys are, the value is always an array?</p>
  
  <p>Thank you and I'm looking forward to your answer!</p>