Problem with d3.nest rollup

gistfile1.txt

<meta charset="utf-8" /><script src="http://d3js.org/d3.v4.min.js"></script><script src="http://d3js.org/queue.v1.min.js"></script><script src="http://d3js.org/topojson.v1.min.js"></script>
<div id="demo">
<div id="data-div">&nbsp;</div>
<script>
var nested_data = []; 
function findTally (nested_data, ward) { 
  for (var index = 0; index < nested_data.length;index++){ 
    var row = nested_data[index]; 
    console.log ("row.key -> " + row.key + " row.value -> " + row.value + " row.values -> " + row.values); 
    var wardin=row.key; 
//    var tallyValue = row.value; 
    if(ward == wardin){ 
    if (row.value === undefined) {return row.values; } else {return row.value;};
    };// end if 
    }; // end for 

  return 0; 
}; // end function 

    d3.csv("http://stopplastics.ca/sites/default/d3_files/ward_petition_counts-1.csv", function(error, tally) {
        var nested_data = d3.nest()
                .key(function(d) { return d.ward; })
                .rollup(function(v) { return v.length; })
                .entries(tally);

   var tally = findTally (nested_data,30);
   console.log ("tally -> " + tally);

    }); // end of csv

</script></div>

Rollup sometimes returns key/values instead of key/value (intermittently although always when I was testing it now.) I had to add the check for key.value === undefined in order to get it to work consistently. I am using this script to create a map (in a Drupal website). http://www.stopplastics.ca/toronto-petition-signatures
(p.s. I'm far from a expert in javascript)