file = [('parent1', ['child1', 'child2', 'child3']),
('parent2', ['child4', 'child5', 'child6']
), ('child1', ['child7', 'child8']), (
'child5', ['child10', 'child33'])]

json_dict = {}
flat_dict = {}

for parent, children in file:
    if parent in flat_dict:
        value = flat_dict[parent]
    else:
        value = {}
        flat_dict[parent] = json_dict[parent] = value
    for child in children:
        flat_dict[child] = value[child] = {}

print(json_dict)