Weird TypeError about the bisector and concaving the sun

I'm tryna make a random username generator (or at least a prototype)

Code I'm using is This:

def Usergenerator():
    word1 = {
        0: 'Good',
        1: 'I',
        2: 'yeet',
        3: 'Not',
        4: 'Fishe',
        5: 'Xx',
        6: 'Ucan',
        7: 'Ultra',
        8: 'Bald',
        9: 'boom',
        10: 'silly'
    }

    word2 = {
        0: 'Milk',
        1: 'Cat',
        2: 'Dog',
        3: 'poo',
        4: 'ghost',
        5: 'Fire',
        6: 'xX',
        7: 'June',
        8: 'Lunar'
    }

    word3 = {
        0: 'Foot',
        1: 'Man',
        2: 'Boy',
        3: 'Poop',
        4: 'Cell',
        5: 'Wat',
        6: 'Burn'
    }

    numbers = {
        0: '12',
        1: '60',
        2: '45',
        3: '11',
        4: '22',
        5: '33',
        6: '78',
        7: '16',
        8: '55'
    }

    import random

    a = 0
    b = len(word1)

    random = random.randint(a, b)
    get = word1.get(random)


    import random

    a = 0
    b = len(word2)

    random = random.randint(a, b)
    get2 = word2.get(random)

    import random

    a = 0
    b = len(word3)

    random = random.randint(a, b)
    get3 = word3.get(random)


    import random

    a = 0
    b = len(numbers)

    random = random.randint(a, b)
    get4 = numbers.get(random)

    Username1 = get + get2 + get3 + get4

    print(Username1)


Usergenerator()

The dictionaries maps numbers from 0 to whatever to a word There are multiple that have different mappings and lengths

it first imports random, then generates a random number, and maps the random number onto the word Then it sets "get" to the result

it does this about 4 times

Then it combines all of the give variables into one, called "Username"

then just prints Username out

this is all in a module which is then ran after its created

But I get this error:

File "c:/Users/why/are/you/here/you/creep.py", line 85, in Usergenerator
    Username1 = get + get2 + get3 + get4
TypeError: can only concatenate str (not "NoneType") to str"