flatten.py

def flatten(d,sep="_"):
    import collections

    obj = collections.OrderedDict()

    def recurse(t,parent_key=""):
        
        if isinstance(t,list):
            for i in range(len(t)):
                recurse(t[i],parent_key + sep + str(i) if parent_key else str(i))
        elif isinstance(t,dict):
            for k,v in t.items():
                recurse(v,parent_key + sep + k if parent_key else k)
        else:
            obj[parent_key] = t

    recurse(d)

    return obj

## TEST EXECUTION BELOW ##
from pprint import pprint

data = {
    "id": 1,
    "first_name": "Jonathan",
    "last_name": "Hsu",
    "employment_history": [
        {
            "company": "Black Belt Academy",
            "title": "Instructor",
            "something": {
                "hello": [1,2,3,{
                    "something":"goes"
                }]
            }
        },
        {
            "company": "Zerion Software",
            "title": "Solutions Engineer"
        }
    ],
    "education": {
        "bachelors": "Information Technology",
        "masters": "Applied Information Technology",
        "phd": "Higher Education"
    }
}

pprint(flatten(data),indent=2)