@raul.07.11 Instead of using SendCommand method, I used a different approach “Editor . WriteMessage () method” and also I have cleaned your dyn graph with just one python. Just Connect Select Objects node to it:
import clr
# Add Assemblies for AutoCAD
clr.AddReference('AcMgd')
clr.AddReference('AcDbMgd')
# Import references from AutoCAD
from Autodesk.AutoCAD.ApplicationServices import *
from Autodesk.AutoCAD.DatabaseServices import *
adoc = Application.DocumentManager.MdiActiveDocument
editor = adoc.Editor
def hatch_area(hatches):
output=[]
obj=[]
errorReport = None
if not isinstance(hatches,list):
hatches = [hatches]
global adoc
with adoc.LockDocument():
with adoc.Database as db:
with db.TransactionManager.StartTransaction() as t:
for hatch in hatches:
handle=hatch.Handle
oid=(db.GetObjectId(False,Handle(int(handle,16)),0))
obj=t.GetObject(oid, OpenMode.ForRead)
try:
if isinstance(obj, Hatch):
area=obj.Area
output.append(area)
# Error handling
except:
import traceback
errorReport = traceback.format_exc()
t.Commit()
if errorReport == None:
return "Area is {}".format(sum(output))
else:
return errorReport
OUT = editor.WriteMessage("\n"+hatch_area(IN[0])+"\n")
Don’t forget to mark the post as solved 
Good Luck!