title: Colon in arguments of a method call - Ruby
body: <p>when looking to some Ruby code I found the following method:</p>
  
  <pre><code>def connection
      unless @_mc_connection &amp;&amp; valid? &amp;&amp; @_ns_version == get_version
        @_mc_connection = ::Dalli::Client.new(self.dalli_servers, self.dalli_options.merge(namespace: namespace))
      end
      @_mc_connection
    end
  </code></pre>
  
  <p>My question is about the use of <code>dalli_options.merge(namespace: namespace)</code>. What is the purpose of the colon here? Is an hash member?</p>