Transform matrix in a vector - Python using numpy

1 a = np.arange(10).reshape(2,5)
2 print a
3 a = a .ravel
4 print a
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2: array([[0, 1, 2, 3, 4],
       [5, 6, 7, 8, 9]])

4: array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])