+ *
+ * If \a cellCor is null (or Py_None) it means that for all #i cell in \a other is equal to cell # i in \a this.
+ *
+ * If \a nodeCor is null (or Py_None) it means that for all #i node in \a other is equal to node # i in \a this.
+ *
+ * So null (or Py_None) returned in \a cellCor and/or \a nodeCor means identity array. This is for optimization reason to avoid building
+ * useless arrays for some \a levOfCheck (for example 0).
+ *