NLog xsi: type doesn't work with custom target

I wanted to write a custom target in NLog using this: https://github.com/nlog/nlog/wiki/How%20to%20write%20a%20Target

and write my logs to MongoDB, so my code looks like this:

namespace NLog.Mongo
{
    [Target("Mongo")]
    public sealed class MongoDBNLogTarget : Target
    {
        ...
        protected override void Write(NLog.LogEventInfo logEvent)
        {
            Repository.Insert(logEvent);
        }
    }
}

      

        
        
        
      

    

and I suppose my NLog.config file should look like this:

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <extensions>
    <add assembly="NLog.Mongo"/>
  </extensions>
  <targets>
    <target name="mongo" xsi:type="Mongo"/>
  </targets>

  <rules>
    <logger name="*" minLevel="Info" writeTo="mongo" />
  </rules>
</nlog>

      

        
        
        
      

    

However, I am getting a warning:

This is an invalid xsi:type 'http://www.nlog-project.org/schemas/NLog.xsd:Mongo'