https://blogofchamodh.blogspot.com/2020/10/generate-all-possible-phone-numbers.html
Here was the first version of the python script that generates crores of telephone numbers. But that script is complex and here is a simple version of the script.
Changes to the product() Function.
I wanted to generate all possible combinations of seven characters and put 7 lists as parameters of the product function but we can do it with only one list instead of seven lists. But you have to set the value 7 for the parameter "repeat" to tell the function you want a combination of seven characters
product_a = product(['1','2','3','4','5','6','7','8','9','0'],repeat=7)
And also you can change the product function as follows.
product_a = product('1234567890',repeat=7)
The above line of code does the same job but shortens our code too
You have another way to do this thing
import string
product_a = product(string.digits,repeat=7)
You can import String as shown above and replace our list parameter with string.digits
and it will give '0123456789' to our function to do the job