code: def _attach_zerodeg_note(docstring, reducer):
      note1 = """
      The {} function will return zero for nodes with no incoming messages.""".format(
          reducer
      )
      note2 = """
      This is implemented by replacing all {} values to zero.
      """.format(
          "infinity" if reducer == "min" else "negative infinity"
      )
  
      docstring = docstring + note1
      if reducer in ("min", "max"):
          docstring = docstring + note2
      return docstring
  
file_path: dgl/python/dgl/ops/spmm.py
imports: import sys
  from ..None import backend
  from ..backend import gspmm, gspmm_hetero
label_desc: Use image node_id 3 for calling a global function with example usage: _attach_zerodeg_note(docstring, reducer) and returns: docstring