input: Write a function to identify and correct the SyntaxError in the given Python program. The function should return the corrected program as a string. The given program is intended to define a function that adds two numbers and prints their sum.
  
  
  def debug_syntax_error(code_str):
      # Identify and correct the syntax error
      ...
      return corrected_code_str
  
  # Test cases
  assert debug_syntax_error('def func(a, b): \n  c = a + b \n  return c\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\nres = func(a, b)\nprint(res)'
  assert debug_syntax_error('def func(a, b): \n  c = a + b \n  return c\nres = func(a, b)\nprint(res)') == 'def func(a, b):\n  c = a + b\n  return c\nres = func(a, b)\nprint(res)'
  assert debug_syntax_error('def func(a, b): \n  c = a + b \n  return c\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\nres = func(a, b)\nprint(res)'
  assert debug_syntax_error('def func(a, b): \n  c = a + b \n  return c\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\nres = func(a, b)\nprint(res)'
  assert debug_syntax_error('def func(a, b): \n  c = a + b \n  return c\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\nres = func(a, b)\nprint(res)'
  
output: def debug_syntax_error(code_str):
      corrected_code_str = code_str.replace('\n  ', '\n    ')
      return corrected_code_str