@JBH late reply, but worth posting:
import clr
clr.AddReference('RevitAPI')
from Autodesk.Revit.DB import *
clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager
doc = DocumentManager.Instance.CurrentDBDocument
views = UnwrapElement(IN[0])
bool = IN[1]
TransactionManager.Instance.EnsureInTransaction(doc)
for view in views:
if bool == True:
view.AreCoordinationModelHandlesHidden = True
result = "Coordination models are hidden"
else:
view.AreCoordinationModelHandlesHidden = False
result = "Coordination models are visible"
TransactionManager.Instance.TransactionTaskDone()
OUT = result