### error

Traceback (most recent call last):
  File ".\ec2_mongo.py", line 208, in <module>
    main()
  File ".\ec2_mongo.py", line 189, in main
    mongo_select_all()
  File ".\ec2_mongo.py", line 108, in mongo_select_all
    mydb, instance_col = set_db()
  File ".\ec2_mongo.py", line 63, in set_db
    instance_col = mydb[instance_col]
TypeError: string indices must be integers


### code
def set_db():
    myclient = connect_db()
    message = "Select Database"
    banner(message)
    today = datetime.today()
    today = today.strftime("%m-%d-%Y")
    if __name__ == '__main__':
        print(Fore.CYAN + "Available MongoDB Databases:")
        if myclient != None:
            # the list_database_names() method returns a list of strings
            database_names = myclient.list_database_names()
            counter = 1
            for db in database_names:
                message = str(counter) + '. ' + db
                print(message)
                counter = counter + 1
        print ("There are", len(database_names), "databases.\n")
        print(f"Please select a database. Enter a number 1 through {len(database_names)}.")
        choice = input("Enter a number: ")
        if is_digit(choice) == True:
            if int(choice) > counter:
                print("Wrong selection.")
                set_db()
            choice = int(choice)
            choice = choice - 1
            mydb = database_names[choice]
            #mydb = myclient['aws_ec2_list']
            print(f"You've selected: {mydb}\n")
        else:
            print("Must enter a digit. Try again.\n")
            set_db()
    else:
        mydb = myclient['aws_ec2_list']
    instance_col = 'ec2_list-' + today
    instance_col = mydb[instance_col]
    return mydb, instance_col