Write a function in Python (ComputeEig) that will take a Hermitian matrix and return its eigenvalues and eigenvectors. In doing this, you will need to check that the matrix that is passed is both square and Hermitian before it performs operations. The function should return the real eigenvalues and the eigenvectors if the matrix is both square and Hermitian. If either is not true, the function should through an error and indicate the problem.