input: def fix_syntax_error(code: str) -> str:
      """
      Detects and fixes Python syntax errors in the given code snippet.
      If a variable assignment is incomplete or if a variable is used but not defined,
      it will be handled with a try-except block.
      
      >>> fix_syntax_error("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:     try:
          exec(code)
      except SyntaxError as e:
          if "invalid syntax" in str(e):
              lines = code.split('\n')
              for i, line in enumerate(lines):
                  if '=' in line and not line.strip().endswith(';'):
                      if not line.strip().endswith(':'):
                          lines[i] = line.rstrip() + ';'
              code = '\n'.join(lines)
          if "name" in str(e):
              lines = code.split('\n')
              for i, line in enumerate(lines):
                  if '=' not in line and not line.strip().startswith('def') and not line.strip().startswith('class'):
                      lines[i] = f"try:\n    {line}\nexcept NameError:\n    print(\"NameError: Name '{line.split()[0]}' is not defined\")"
              code = '\n'.join(lines)
      return code