<?xml version="1.0" encoding="utf-8"?><HelpTOCNode Title="ContainsKey Method " Url="html/Overload_Independentsoft_Sip_Header_ContainsKey.htm"><HelpTOCNode Title="ContainsKey Method (String)" Url="html/M_Independentsoft_Sip_Header_ContainsKey_1.htm" /><HelpTOCNode Title="ContainsKey Method (StandardHeader)" Url="html/M_Independentsoft_Sip_Header_ContainsKey.htm" /></HelpTOCNode>