input: Write a function to print the length of a given string.
  
  assert string_length("Python")=="Length of the given string is: 6"
  assert string_length("Hello")=="Length of the given string is: 5"
  assert string_length("")=="Length of the given string is: 0"
  assert string_length("12345")=="Length of the given string is: 5"
output: def string_length(s):
      return f"Length of the given string is: {len(s)}"