input: Write a function to print the length of a given string.
  string = "Python"
  print("Length of the given string is:", len(string))
  assert length_of_string("Python")==None
  assert length_of_string("Hello")==None
  assert length_of_string("12345")==None
  assert length_of_string("")==None
output: def length_of_string(s):
      print("Length of the given string is:", len(s))