This is your first python node in Dynamo.

myFirstPythonNode.py

# import the common language runtime to communicate with the Revit API
import clr

# import the revit api
clr.AddReference('RevitAPI')
from Autodesk.Revit.DB import *

# import dynamo's revit nodes
clr.AddReference('RevitNodes')
import Revit
clr.ImportExtensions(Revit.GeometryConversion)
clr.ImportExtensions(Revit.Elements)

# import Revit's transaction manager
clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager

# reference the active document
doc = DocumentManager.Instance.CurrentDBDocument
uidoc=DocumentManager.Instance.CurrentUIApplication.ActiveUIDocument

#Preparing input from dynamo to revit
element = UnwrapElement(IN[0])
boolean = IN[1]

#Do some action in a Transaction
TransactionManager.Instance.EnsureInTransaction(doc)
# pin the element using this https://apidocs.co/apps/revit/2023/c37bc7f9-409e-9b8a-f491-f700228985e2.htm
element.Pinned = boolean
TransactionManager.Instance.TransactionTaskDone()

OUT = element