question: returns the successor or children nodes of this graphnode . concode_field_sep int preIndex concode_elem_sep int postIndex concode_elem_sep HashSet succs concode_elem_sep HashSet preds concode_field_sep int preOrderIndex concode_elem_sep int postOrderIndex concode_elem_sep void setPostOrderIndex concode_elem_sep void setPreOrderIndex concode_elem_sep Collection preds
target: Collection function ( ) { return succs ; }