an><span data-unresolved-link="kotlinx.serialization/Serializable///PointingToDeclaration/"><span class="token annotation builtin">Serializable</span></span></div></div><span class="token keyword">data </span><span class="token keyword">class </span><a href="index.html">GetTransactionHashesRequestParams</a><span class="token punctuation">(</span><span class="parameters "><span class="parameter "><span class="token keyword">val </span>firstBlockIndex<span class="token operator">: </span><a href="https://kotl