Question: What am I doing wrong with this procedure?

So I'm trying to make a procedure to tell is a sequence is graphical or not.
seqgraph:= proc (L::list)

local k::integer, i::integer, n::integer, a::integer, S;

n := numelems(L);

S := convert(L, `+`);

a := 0;

if type(S, odd) then print("not graphical")

else for k to n do

if add(L[i], i = 1 .. k) <= k(k-1)+add(min(k, L[i]), i = k+1 .. n) then a := a+1

else a := a+2

end if;

end do;

end if;
if n = a then print(graphical)

else print("not graphical")

end if;

end proc;

 I'm trying to say that if that equality (which is part of the erdos gallai theorem) holds for that value of k then we'll add one to a value (a). Thus, if a=n at the end then the ineuqality was true for each k and thus it would it should print "graphical" but every list I test it one prints 'not graphical'. Where is my mistake? I get an error saying it can't execute add?