title: pine script error- An argument of 'series string' type was used but a 'const string' is expected
body: <p>when I am trying to pass date to timestamp() function I am getting error &quot;Cannot call 'timestamp' with argument 'dateString'='date_bluex5'. An argument of 'series string' type was used but a 'const string' is expected&quot;</p>
  <p>what can be the solution for this. How can I convert a series string to a constant string?</p>
  <p>Following is the code I used</p>
  <pre><code>//@version=5
  indicator(&quot;My Script&quot;)
  box_plot_found_blue=ta.crossover(close,ta.sma(close,200))
  int yrx5 = ta.valuewhen(box_plot_found_blue, dayofmonth(time), 5)
  int mox5 = ta.valuewhen(box_plot_found_blue, month(time), 5)
  int dax5 = ta.valuewhen(box_plot_found_blue, year(time), 5)
  
  date_bluex5 = str.tostring(math.round(yrx5)) + '/' + str.tostring(math.round(mox5)) + '/' + str.tostring(math.round(dax5))
  
  targetTime = timestamp(date_bluex5)
  bgcolor(targetTime == time ? color.silver : na)
  </code></pre>
  <p>how can I convert a series string to a constant string?</p>