 class="arrow">&#45;&gt;</span></span>
  <span><span class="type-var">'a</span> option</span></span></code></div><div class="spec-doc"><p>extract the postcondition for a node id from the given invariant map</p></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-extract_pre"><a href="#val-extract_pre" class="anchor"></a><code><span><span class="keyword">val</span> extract_pre : 
  <span><a href="argument-1-T/CFG/Node/index.html#type-id">TransferFunctions.CFG.Node.id</a> <span class="a