title: Access HASH_TABLE element eiffel
body: <p>I have this simple code, I'd like to access an element in an ARRAYED_SET what is in a HASH_TABLE, but I get an error:</p>
  
  <pre><code>Error: target of the Object_call might be void.
  What to do: ensure target of the call is attached.
  </code></pre>
  
  <p>here's my code:</p>
  
  <pre><code>class
  APPLICATION
  
  inherit
      ARGUMENTS
  
  create
      make
  
  feature {NONE}
  make
  local
  
      elem: ARRAYED_SET[INTEGER]
      table: HASH_TABLE[ARRAYED_SET[INTEGER], INTEGER]
  do
      create elem.make (3)
      create table.make (1)
  
      elem.put (4)
      table.put (elem, 1)
  
      table.at (1).go_i_th (1)
  end
  end
  </code></pre>