ianakelly/ImportError: No module named 'firebase_admin'

I got TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'

Hey, I tried running the code but it gives me the same error:

pi@raspberrypi:~/Desktop/pyfirebase $ sudo python triall.py
Traceback (most recent call last):
File "triall.py", line 1, in
import firebase_admin.py
ImportError: No module named firebase_admin.py

I downloaded sudo pip3 install firebase_admin on my raspberry

and here is my code:
import firebase_admin

from firebase_admin import credentials
from firebase_admin import db

cred = credemtials.Certificate('firebase.json')
firebase_admin.initialize_app(cred,{
'databaseURL' : "https://raspberry-pi-197b8.firebaseio.com/"
})

ref = db.reference ('/')
ref.set ({
"employees":{
{"firstName":"John", "LastName" :" Doe"},
{"firstName" :"Anna", "lastName" : "Smith"},
{"firstName" : "Peter", "lastName" : "Jones"}
}
})

thank you in advance