input: Write a function to calculate the combined length of two input strings. The function should return the total number of characters in both strings combined.
  
  
  def get_string_length(string_1, string_2):
      return len(string_1 + string_2)
  
  assert get_string_length("Hello", "World")==10
  assert get_string_length("Python", "Programming")==17
  assert get_string_length("", "")==0
  assert get_string_length("123", "456")==6
  assert get_string_length("Test", "")==4
  
output: def get_string_length(string_1, string_2):
      return len(string_1 + string_2)