pylib/gyp/xcodeproj_file.py:784:20: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks

pylib/gyp/xcodeproj_file.py:794:51: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks

pylib/gyp/xcodeproj_file.py:809:44: E721 Use `is` and `is not` for type comparisons, or `isinstance()` for isinstance checks