String error when using selmer.parser/render-file

I am trying out luminus. but when trying to call a html file using:

(selmer.parser/render-file "vars.html" {})

I get this error:

java.lang.IllegalArgumentException: contains? not supported on type: java.lang.String

but if I try this in the repl it works:

> (selmer.parser/render-file "vars.html" {})
> "<html>\n  <head>\n    <meta http-equiv= \"Content-Type\" content= \"text/html; charset=UTF-8\" />\n    <title>vars</title>\n  </head>\n  <body>\n    <ul>\n      \n      <p></p>\n          <ul>\n      \n      <p></p>\n\n      <h2>HTML Forms</h2>\n\n      <form action=\"/data\">\n\t<label for=\"text1\">text1</label><br>\n\t<input type=\"text\" id=\"text1\" name=\"text1\" value=\"John\"><br>\n\t<label for=\"text2\">text2</label><br>\n\t<input type=\"text\" id=test2\" name=\"text2\" value=\"Doe\"><br><br>\n\t<input type=\"submit\" value=\"Submit\">\n      </form>\n         <form action=\"/data2\">\n\t<input type=\"text\" id=\"t1\" name=\"t1\" value=\"John\"><br>\n\t<input type=\"text\" id=test2\" name=\"t2\" value=\"Doe\"><br><br>\n\t<input type=\"submit\" value=\"Submit\">\n      </form>\n      <p>you entered this:  and  </p>\n  </body>\n</html>\n"

Any suggestions?

so I found out that contains? require a dict and a key to check if it is in the dict. But that does not give a clue why it works in the repl and not when calling from the website.