kw pkg">R6</span><span class="kw ns">::</span><span class="fu"><a href="https://rdrr.io/pkg/R6/man/R6Class.html">R6Class</a></span>(
  <span class="kw">inherit</span> <span class="kw">=</span> <span class="no">Policy</span>,
  <span class="kw">public</span> <span class="kw">=</span> <span class="fu"><a href="https://rdrr.io/r/base/list.html">list</a></span>(
    <span class="kw">first</span> <span class="kw">=</span> <span class="kw">NULL</span>,
    <span class="kw">class_name</span> <span class="kw">=</sp