code: function isCyclic (data) {
      
      // Create an array that will store the nodes of the array that have already been iterated over
      let seenObjects = [];
  
      function detect (data) {
          // If the data pass is an object
          if (data && getType(data) === "Object") {
              
              // If the data is already in the seen nodes array then we know there is a circular reference
              // Therefore return true
              if (seenObjects.indexOf(data) !== -1) {
                  return true;
              }
  
              // Add the data to the seen objects array
              seenObjects.push(data);
  
              // Begin iterating through the data passed to the method
              for (var key in data) {
                  // Recall this method with the objects key
                  if (data.hasOwnProperty(key) === true && detect(data[key])) {
                      return true;
                  }
              }
          }
          return false;
      }
  
      // Return the method
      return detect(data);
  }
docs: Create a method to detect whether an object contains a circular reference