rm_effect_ (r:[]) iii@(i:ii) =
    if r<i then (i-1):ii
    else if r==i then error "Invalid insertion point"
    else iii
rm_effect_ (r:[]) iii@(i:ii) =
    if r<i then (i-1):ii
    else if r==i then error "Invalid insertion point"
    else iii
rm_effect_ (r:[]) iii@(i:ii) =
    if r<i then (i-1):ii
    else if r==i then error "Invalid insertion point"
    else iii