input: def fix_syntax_errors(code: str) -> str:
      """Given a code snippet, detect and fix Python syntax errors by converting 
      undefined variable references into try-except blocks.
      >>> fix_syntax_errors("def test ():\n    x = 5\n    y = 3\n    z")
      "def test():\n    x = 5\n    y = 3\n    try:\n        z\n    except NameError:\n        print(\"NameError: Name 'z' is not defined\")"
      """
output:     lines = code.split('\n')
      fixed_lines = []
      for line in lines:
          if '=' not in line and not line.strip().startswith('#'):
              try_except_block = f"    try:\n        {line.strip()}\n    except NameError:\n        print(\"NameError: Name '{line.strip().split()[0]}' is not defined\")"
              fixed_lines.append(try_except_block)
          else:
              fixed_lines.append(line)
      return '\n'.join(fixed_lines)