Question: what is syntax for solving 4th order ODE, BVP problem?

I am learning how to use Maple with boundary value ODE. Given this ODE

y''''(x)+ lam* y(x) =0

with some B.C., say  y(0)=0,y'(0)=0,y''(L)=0,y'''(L)=0, where L is length.

I can't figure the correct syntax to use. It seems Maple do not like the syntax I am using, but it works on a second order ODE?

Here is my attempt:

restart;
assume(lam>0); assume(L>0);
bc:=y(0)=0,D[1](y)(0)=0,D[2](y)(L)=0,D[3](y)(L)=0;
dsolve({diff(y(x),x$4)+lam*y(x)=0,bc},y(x));

Error is 

Error, (in evalapply) too few variables for the derivative with respect to the 2nd variable
Error, (in dsolve) found the following equations not depending on the unknowns of the input system: {bc}

But on a simpler second order ODE, the syntax works

restart;
assume(lam>0); assume(L>0);
bc:=y(0)=0,D[1](y)(0)=0;
dsolve([diff(y(x),x$2)+lam*y(x)=0,bc],y(x));

No error. 

Is the syntax I am using in first example wrong? what would be the correct syntax? I googled for long time, and can't find one example that shows how to use BVP with higher order ODE. I am Maple newbie.

 

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