Not Able to Get Portal Items Dependent To specific Item

[BHK]

I have a Feature Service Item on Portal with Item ID = wedr22sdb7242378c833730c9sss2sauf

now I need to find out all Maps, Views, Apps and ... which are using this (or are dependent to this item) item

item = gis.content.get('wedr22sdb7242378c833730c9sss2sauf')

dependent_items = item.dependent_to()
for dependent_item in dependent_items:
    print(dependent_item)

but I am getting this error message, in retune 

AttributeError: 'NoneType' object has no attribute 'dependent_to'

Can you please let me know what I am missing or doing wrong?

[Dan_Brumm]

This maybe completly obvious but that item variable has a value right? The error messages seems to point at the item being Nothing??   Also this is for Enterprise not AGOL? 

dependent_to()¶

The dependent_to method returns items, urls, etc that are dependent to this item.

NOTE

This method only available for items in an ArcGIS Enterprise organization.