code: def test_mask_flags_rgba():
      with rasterio.open("tests/data/RGBA.byte.tif") as src:
          for flags in src.mask_flag_enums[:3]:
              assert MaskFlags.nodata not in flags
              assert MaskFlags.per_dataset in flags
              assert MaskFlags.alpha in flags
          assert [MaskFlags.all_valid] == src.mask_flag_enums[3]
  
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 3 for calling a global function with example usage: test_mask_flags_rgba() without return types