label">label</a> * <a href="#type-state">state</a>)</span> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-t">t</a> <span class="arrow">&#45;&gt;</span></span> <a href="#type-t">t</a></span></code></div><div class="spec-doc"><p><code>add_transition (q1,l,q2) s</code> returns the LTSA obtained by adding transition from state <code>q1</code> to state <code>q2</code>, with label <code>l</code> to LTSA <code>s</code>. Raises <code>Invalid_state</code> if <code>q1</code> or <code>q2</code> are n