How to resize numpy.memmap without copying?

Question

Python

Code works but changes are not saved

def test_resize_inplace():

    fA = np.memmap('A_r.npy', dtype='uint8', mode='w+', shape=(3,12))

    print "fA"
    print fA

    fA[2][0] = 42

    # resize by creating new memmap
    new_fA = np.memmap('A_r.npy', mode='r+', dtype='uint8', shape=(20,12))

    print 'fA'
    print fA

    print 'new_fA'
    print new_fA

moreover, if I try to put the resize into a separate procedure, the interpreter collapses on the line
print new_fA

def resize_memmap(fm,sz,tp):
    fm.flush()
    print fm.filename
    new_fm = np.memmap(fm.filename, mode='r+', dtype= tp, shape=sz)
    return new_fm

def test_resize_inplace():

    fA = np.memmap('A_r.npy', dtype='uint8', mode='w+', shape=(3,12))

    print "fA"
    print fA

    fA[2][0] = 42

    sz= (20,12)
    tp= 'uint8'

    new_fA= resize_memmap(fA,sz,type)
    new_fA[9][9]= 111

    print 'fA'
    print fA

    print 'new_fA'
    print new_fA