input: Write a python function to find all numbers in a string and calculate their sum.
  assert sum_numbers_in_string("My age is 25 and my friend's age is 30.") == 55
  assert sum_numbers_in_string("There are 3 cats and 4 dogs.") == 7
  assert sum_numbers_in_string("No numbers here!") == 0
output: def sum_numbers_in_string(s):
      import re
      return sum(map(int, re.findall(r'\d+', s)))