def make_Hamiltonian(pauli_list):
    """Creates a matrix operator out of a list of Paulis.

    Args:
        pauli_list : list of list [coeff,Pauli]
    Returns:
        A matrix representing pauli_list
    """
    Hamiltonian = 0
    for p in pauli_list:
        Hamiltonian += p[0] * p[1].to_matrix()
    return Hamiltonian