code: def source(src, dst):
      if src & 0xFF000000:
          return src
      else:
          return dst
  
file_path: datashader/datashader/composite.py
imports: from __future__ import annotations
  import numba
  import numpy
  import os
label_desc: Use image node_id 5 for calling a global function with example usage: source(src, dst) and returns: src, dst