Question: PARTIAL DIFFERENTIAL EQUATION SYSTEM

I'm trying to solve a system that contains the Laplace homogeneous equation and the boundary/initial conditions, thus i'm typing the following code:

> LAPLACE := (D[1, 2](u))(x, y)+(D[2, 2](u))(x, y) = 0;

            D[1, 2](u)(x, y) + D[2, 2](u)(x, y) = 0

> sys[1] := [LAPLACE, u*(x, 0) = 0, u(0, y) = 0, u(1, y) = 0, u(x, 1) = x^2*(1-x)];

[(D[1, 2](u))(x, y)+(D[2, 2](u))(x, y) = 0, u*(x, 0) = 0, u(0, y) = 0, u(1, y) = 0, u(x, 1) = x^2*(1-x)]

but when i use the command pdsolve(sys[1]) the message below appears:

"Error, (in pdsolve/sys/info) ambiguous input: the variables {u} and the functions {u(0, y), u(1, y), u(x, 1), u(x, y)} cannot both appear in the system"
 

So, it seems the declaration of the system isn't correct, but it's exactly how the tutorial of the maplesoft shows it. Could you please make clear what is a system of pde for maple and what is the correct tool for solving a system with boundary/initial conditions?