class="material-icons"></i></a></span> <span class="modifier_kind"><span class="modifier"></span> <span class="kind">def</span></span> <span class="symbol"><span class="implicit">ensuring</span><span class="params">(<span name="cond">cond: (<a href="" name="provingground.induction.TypObj" id="provingground.induction.TypObj" class="extype">TypObj</a>[<span name="provingground.induction.TypObj.T" class="extype">T</span>, <span name="provingground.induction.TypObj.C" class="extype">C</span>]) =&gt; <span na