numpy.random.shuffle returns None

Question

I installed numpy1.8.2 and then I tried the following code:

import numpy as np
a = np.arange(10)
print a, np.random.shuffle(a)

but

Answer 1

Sir, it must output that way. .shuffle() returns None

>>> import numpy as np
>>> print np.random.shuffle.__doc__

    shuffle(x)

        Modify a sequence in-place by shuffling its contents.

        Parameters
        ----------
        x : array_like
            The array or list to be shuffled.

        Returns
        -------
        None

        Examples
        --------
        >>> arr = np.arange(10)
        >>> np.random.shuffle(arr)
        >>> arr
        [1 7 5 2 9 4 3 6 0 8]

        This function only shuffles the array along the first index of a
        multi-dimensional array:

        >>> arr = np.arange(9).reshape((3, 3))
        >>> np.random.shuffle(arr)
        >>> arr
        array([[3, 4, 5],
               [6, 7, 8],
               [0, 1, 2]])