code: def test_mask_flags():
      with rasterio.open("tests/data/RGB.byte.tif") as src:
          for flags in src.mask_flag_enums:
              assert MaskFlags.nodata in flags
              assert MaskFlags.per_dataset not in flags
              assert MaskFlags.alpha not in flags
  
file_path: rasterio/tests/test_band_masks.py
imports: import numpy
  import pytest
  import rasterio
  from rasterio.enums import MaskFlags
  from rasterio.errors import NodataShadowWarning
label_desc: Use image node_id 2 for calling a global function with example usage: test_mask_flags() without return types