docs: def _genenare_callmap_sif(self, filepath):
          """
          Generate a sif file from the call map.
  
          :param filepath:    Path of the sif file
          :return:            None
          """
          with open(filepath, "wb") as f:
              for src, dst in self.callgraph.edges():
                  f.write("%#x\tDirectEdge\t%#x\n" % (src, dst))