try yourself |run program

class A:
    name="Atul"
    city="Buxar"
    
class B:
    name="Mohit"
    city="Delhi"
    
class C:
    name="Rahul"
    city="Patna"
    
userlist = [A(),B(),C()]

newuserlist = []
for obj in userlist:
    user = {}
    user["name"] = obj.name
    user['city'] = obj.city
    newuserlist.append(user)

print(newuserlist)

# using comprehension
newuserlist = []
newuserlist = [{"name":obj.name,"city":obj.city}for obj in userlist]
print(newuserlist)

Program Output

[{'name': 'Atul', 'city': 'Buxar'}, {'name': 'Mohit', 'city': 'Delhi'}, {'name': 'Rahul', 'city': 'Patna'}]
[{'name': 'Atul', 'city': 'Buxar'}, {'name': 'Mohit', 'city': 'Delhi'}, {'name': 'Rahul', 'city': 'Patna'}]