revert mult code change, adding documentation on using np.array
revert mult code change, adding documentation on using np.array

atilag/qiskit-sdk-py,QISKit/qiskit-sdk-py,atilag/qiskit-sdk-py,QISKit/qiskit-sdk-py,QISKit/qiskit-sdk-py,atilag/qiskit-sdk-py