n class="ruby-identifier">raise</span> <span class="ruby-constant">ArgumentError</span>, <span class="ruby-string">&quot;Must provide an Array :as option&quot;</span>
  <span class="ruby-keyword">end</span>
  <span class="ruby-identifier">bitmask_definitions</span>[<span class="ruby-identifier">attribute</span>] = <span class="ruby-constant">Definition</span>.<span class="ruby-identifier">new</span>(<span class="ruby-identifier">attribute</span>, <span class="ruby-identifier">options</span>[<span class="rub