<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.ConstructorSeqTL" id="provingground.induction.ConstructorSeqTL" class="extype">ConstructorSeqTL</a>[<span name="provingground.induction.ConstructorSeqTL.SS" class="extype">SS</span>, <span name="provingground.induction.ConstructorSeqTL.H" class="extype">H</span>, <span