cosmos change feed azure function

cosmos change feed azure function.csx

using Microsoft.Azure.Documents;
using System.Collections.Generic;
using System;

public static async Task Run(IReadOnlyList<Document> input, TraceWriter log)
{
    foreach(var changeInput in input)
    {
        if(changeInput.GetPropertyValue<string>("city") == "colombo")
        {
            log.Verbose("Something has happened in Colombo");
        }
        else
        {
            log.Verbose("Something has happened in somewhere else");
        }
    }
    
    log.Verbose("Document count " + input.Count);
	log.Verbose("First document Id " + input[0].Id);
}