Counting numbers in a String

Design a function that given a text string, returns the numbers that appear in the string. For example, the string ‘a 1, a 201, and 2 ones’ contains 3 numbers: 1, 201, and 2.

>>> nums_in_string("a 1, a 201 and 2 ones")
    3
>>> nums_in_string("without numbers")
    0
>>> nums_in_string("2345543")
    1

Write pytests to test your function in an automated way.