Hide all children of selected items

import bpy

def recursiveSelect(parent):
    for child in parent.children:

        child.select_set(True)

        if child.children:
            recursiveSelect(child)

initialSelection = bpy.context.selected_objects

for obj in initialSelection:
    recursiveSelect(obj)

for obj in bpy.context.selected_objects:
    obj.hide_set(True)