input: Write a function to debug the given Python program which raises a SyntaxError. The function should return the corrected code as a string.
  assert debug_syntax("def func(a, b): \n  c = a + b \n  return c \n\na = 4 \n b = 5 \n\nres = func(a, b) \nprint(res)")=='def func(a, b):\n  c = a + b\n  return c\n\na = 4\nb = 5\n\nres = func(a, b)\nprint(res)'
  assert debug_syntax("") == ''
  assert debug_syntax("def func(a, b):\n  c = a * b \n return c") == 'def func(a, b):\n  c = a * b\n  return c'
  assert debug_syntax("def func(a, b):\n  c = a + b\n  d = a - b \n return c + d") == 'def func(a, b):\n  c = a + b\n  d = a - b\n  return c + d'
  assert debug_syntax("print('Hello, World!')") == "print('Hello, World!')"
output: def debug_syntax(code):
      return code.replace('\n ', '\n  ')