I’ve commented the code here, and now taken into account, that the input may be a single item or a list of items:
from Autodesk.Revit.DB import *
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager
#Import ToDSType(bool) extensions method
doc = DocumentManager.Instance.CurrentDBDocument
#Input should be the elements and not the element id's
#Use the ifinstance() built in python function to check if the input is a list or a single object.
#This is a common way to solidify the code incase inputs can be either a list of items or a single item:
#Read more here: https://docs.python.org/2/library/functions.html#isinstance
#if its a list object, iterate through it, and unwrap the elements.
if isinstance(IN, list):
panels = [UnwrapElement(i) for i in IN]
#if its a single item, it will be unwrapped in a list with a single item
panels = [UnwrapElement(IN)]
#Create an empty list to hold the output
output = 
#Iterate through the list with a for loop
for i in panels:
TransactionManager.Instance.EnsureInTransaction(doc) #We're making changes to the document, thus a transaction is needed
#The create method used takes the document and an element ID as inputs.
#So we're iterating through each panel and call the Id property of the family instance by using dot notation.
#Use the .ToDSType(False) as we're creating new non-Revit owned elements
#See here for family instance properties http://www.revitapidocs.com/2018.1/9235095b-b7ae-b6e5-6cc2-2b8d397644de.htm
#See here for Dynamo python migration https://github.com/DynamoDS/Dynamo/wiki/Python-0.6.3-to-0.7.x-Migration#revitapi
#Assign your output to the OUT variable.
OUT = output
Personally, I’d always use the actual element as input, and the call the ID from inside the code, but it can ofcause also be set up with the element ID as input.
Hope it helps