System.Xml.Xsl.XslTransformException: Extension object 'http://www.efterskole.com/ef' does not contain a matching 'GetPriceCalculationSelectedYear' method that has 0 parameter(s).
   at System.Xml.Xsl.Runtime.XmlExtensionFunction.Bind()
   at System.Xml.Xsl.Runtime.XmlExtensionFunctionTable.Bind(String name, String namespaceUri, Int32 numArgs, Type objectType, BindingFlags flags)
   at System.Xml.Xsl.Runtime.XmlQueryContext.InvokeXsltLateBoundFunction(String name, String namespaceUri, IList`1[] args)
   at selectedYearId(XmlQueryRuntime {urn:schemas-microsoft-com:xslt-debug}runtime)
   at Execute(XmlQueryRuntime {urn:schemas-microsoft-com:xslt-debug}runtime)
   at System.Xml.Xsl.XmlILCommand.Execute(Object defaultDocument, XmlResolver dataSources, XsltArgumentList argumentList, XmlSequenceWriter results)
   at System.Xml.Xsl.XmlILCommand.Execute(Object defaultDocument, XmlResolver dataSources, XsltArgumentList argumentList, XmlWriter writer)
   at System.Xml.Xsl.XslCompiledTransform.Transform(IXPathNavigable input, XsltArgumentList arguments, XmlWriter results, XmlResolver documentResolver)
   at Mvp.Xml.Common.Xsl.MvpXslTransform.TransformToWriter(XmlInput defaultDocument, XsltArgumentList xsltArgs, XmlWriter xmlWriter)
   at Mvp.Xml.Common.Xsl.MvpXslTransform.Transform(XmlInput input, XsltArgumentList arguments, XmlOutput output)
   at Sitecore.Web.UI.WebControls.XslFile.DoRender(HtmlTextWriter output, Item item) Xsl file could not be processed: /xsl/Nemetos/Efterskole/Schools/SearchListFotIframe.xslt