Question: Why I am getting empty plot?

Dear all,

restart:with(plots):
eq1:=diff(f(y), y$4)-(diff(f(y), y$2));

bcs:=f(h1) = (1/2), f(h2) = -(1/2), (D(f))(h1) = -1, (D(f))(h2) = -1:

h1:= 1+cos(x):h2:=-1-cos(x+g):

db:=eq1,bcs:
d1 := subs(g=1,[db]):
P1:= eval(diff(diff(f(y),y$2)-f(y),y));

for x from 0 to 1 by 0.1 do
F2[x]:=dsolve(d1, numeric,maxmesh=25500,output=listprocedure): 
P2[x]:=subs(F2[x],P1); # subing values into P1 
end do:
Vls:=Vector([seq(P2[x],x=0..1,0.1)]):
XX := `<|>`(`<,>`(seq(x, x = 0..1, 0.1))):
plot(<<XX>|<Vls>>, color=red);

I'm trying to plot P1 vs x but getting empty plot. Please help me out. 

Thanks

 

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