lass='period'>.</span><span class='id identifier rubyid_is_a?'>is_a?</span> <span class='const'>Array</span>
    <span class='id identifier rubyid_raise'>raise</span> <span class='const'>ArgumentError</span><span class='comma'>,</span> <span class='tstring'><span class='tstring_beg'>&quot;</span><span class='tstring_content'>Expected an array, but got a </span><span class='embexpr_beg'>#{</span><span class='id identifier rubyid_args'>args</span><span class='lbracket'>[</span><span class='int'>0</span><span 