input: Write a function to convert PascalCase strings to hyphen-separated lowercase strings.
  assert convert_pascal_to_hyphen("HelloWorld") == "hello-world"
  assert convert_pascal_to_hyphen("ConvertPascalToHyphen") == "convert-pascal-to-hyphen"
  assert convert_pascal_to_hyphen("ThisIsATest") == "this-is-a-test"
output: def convert_pascal_to_hyphen(s):
      result = []
      for char in s:
          if char.isupper():
              if result:
                  result.append('-')
              result.append(char.lower())
          else:
              result.append(char)
      return ''.join(result)