input: Write a function to convert a given string to a different case using the swapcase method in Python. The function should return the new string with cases swapped.
  assert convert_string_case("this Is A TeST")=="THIS iS a tEst"
  assert convert_string_case("Hello World!")=="hELLO wORLD!"
  assert convert_string_case("Python")=="pYTHON"
  assert convert_string_case("a1b2c3")=="A1B2C3"
  assert convert_string_case("")==""
output: def convert_string_case(s):
      return s.swapcase()