keys_to_overwrite</span><span class='comma'>,</span> <span class='op'>&amp;</span><span class='id identifier rubyid_block'>block</span><span class='rparen'>)</span>
  <span class='comment'># Lazy initialize butto_defaults store if it hasn&#39;t been yet
</span>  <span class='const'>RequestStore</span><span class='period'>.</span><span class='id identifier rubyid_store'>store</span><span class='lbracket'>[</span><span class='symbol'>:button_defaults</span><span class='rbracket'>]</span> <span class='op'>||=<