-&gt; b) (b -&gt; a)
</span
	  ><a href="Classes.html#plugh"
	  ><span class="hs-identifier hs-var hs-var hs-var"
	    >plugh</span
	    ></a
	  ></span
	></span
      ><span
      > </span
      ><span class="hs-special"
      >(</span
      ><span class="annot"
      ><span class="hs-identifier hs-type"
	>Left</span
	></span
      ><span
      > </span
      ><span id=""
      ><span class="annot"
	><span class="annottext"
	  >a
</span
	  ><a href="#"
	  ><span class="hs-identifier hs-var"
	    >a</span
	