Question: Why unterminated procedure error?

evolf := proc(f);
h1 := z + f(x);
h2 := z - f(x);
h3 := z*f(x);
h4 := f(x)/z;
h5 := z+diff(f(x),x);
h6 := z-diff(f(x),x);
h7 := z*diff(f(x),x);
h8 := diff(f(x),x)/z;
h9 := subs(x=z, f(x));
test := [h1, h2, h3, h4, h5, h6, h7, h8, h9];
F = 0;
for i from 1 to 9 do
    F = F + 1/(1+exp(subs(x=0,test[i])-subs(x=0,f(x))));
end proc;            

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