Random password generator with choice of three strengths
A flexible and manageable approach would be to create a custom PasswordGenerator which will comprise all functionality for particular password levels. Putting it a separate module, thus it can be imported and used in any place of an application on demand.

The one of possible implementations (considering your conditions):

password_generator.py :

import string
import random


class PasswordGenerator:

    LOWERCASE = string.ascii_lowercase[:26]
    UPPERCASE = string.ascii_uppercase[:26]
    NUMBERS = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
    SPECIAL_CHARS = ["*", "&amp;", "@", "!"]
    LEVELS = ("weak", "medium", "strong")   # password levels

    @staticmethod
    def _compose_passphrase(iter_num, char_types):
        return ''.join(random.choice(c_type) for i in range(iter_num)
                       for c_type in char_types)

    @classmethod
    def weak(cls):
        iter_num = 6    # number of iterations
        char_types = (cls.LOWERCASE,)
        return cls._compose_passphrase(iter_num, char_types)

    @classmethod
    def medium(cls):
        iter_num = 5
        char_types = (cls.LOWERCASE, cls.UPPERCASE)
        return cls._compose_passphrase(iter_num, char_types)

    @classmethod
    def strong(cls):
        iter_num = 2
        char_types = (cls.LOWERCASE, cls.UPPERCASE, cls.NUMBERS, cls.SPECIAL_CHARS)
        return cls._compose_passphrase(iter_num, char_types)


Client script prompt_password.py :

from password_generator import PasswordGenerator

while True:
    choice = input("Want to create a password? To make your choice for your password strength, "
                   "please respond with one of the following: weak/medium/strong ")

    if choice in PasswordGenerator.LEVELS:
        print(getattr(PasswordGenerator, choice)())   # calling a respective method (password level)
    else:
        break




Running prompt_password.py:

Want to create a password? To make your choice for your password strength, please respond with one of the following: weak/medium/strong weak
ylwwcj
Want to create a password? To make your choice for your password strength, please respond with one of the following: weak/medium/strong weak
kktnkx
Want to create a password? To make your choice for your password strength, please respond with one of the following: weak/medium/strong medium
jLiAoWaHbA
Want to create a password? To make your choice for your password strength, please respond with one of the following: weak/medium/strong strong
qG8@sM7*
Want to create a password? To make your choice for your password strength, please respond with one of the following: weak/medium/strong strong
tY8&amp;eL7@
Want to create a password? To make your choice for your password strength, please respond with one of the following: weak/medium/strong best


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