input:                 Write a function to debug and fix the given Python program which raises a SyntaxError. The function should take the erroneous code as input, fix the syntax error if any, and return the corrected code.
  assert debug_code("def func(a, b): \nc = a + b \nreturn c \n\na = 4 \nb = 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_code("def func(a, b): c = a + b \nreturn c \n\na = 4 \nb = 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_code("def func(a, b):\nc = a + b \n return c \n\na = 4 \nb = 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_code("def func(a, b):\n c = a + b \n return c \n\na = 4\nb = 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_code("def func(a, b):\n c = a + b \n return c \n\na = 4\nb = 5 \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)"
output:     
  def debug_code(code: str) -> str:
      lines = code.split('\n')
      corrected_lines = []
      for line in lines:
          if line.strip().startswith('return'):
              corrected_lines.append('  ' + line.strip())
          elif line.strip() and not line.startswith('def'):
              corrected_lines.append('  ' + line)
          else:
              corrected_lines.append(line)
      return '\n'.join(corrected_lines)
  