input: Write a function to calculate the combined length of two strings. The function should take in two string inputs and return the total length of the concatenated string.
  assert get_string_length("Hello", "World") == 10
  assert get_string_length("Python", "Programming") == 19
  assert get_string_length("", "Java") == 4
  assert get_string_length("Swift", "") == 5
  assert get_string_length("", "") == 0
output: def get_string_length(str1, str2):
      return len(str1 + str2)