Merge dicts without override

[perfringo]

ichabod801 algorithm expressed in Python code:

combined = dict()
                                                      
for d in (alias, vitals, combine): 
    for key, value in d.items(): 
        try: 
            combined[key].update(value) 
        except KeyError: 
            combined[key] = dict(value)

If defaultdict is OK then code can be even simpler:

combined = defaultdict(dict)                                               

for d in (alias, vitals, combine): 
    for key, value in d.items(): 
        combined[key].update(value)