strange numpy behaviour

[George Trojan]

This does not look right:

dilbert at gtrojan> python3.4
Python 3.4.1 (default, Jul  7 2014, 15:47:25)
[GCC 4.8.3 20140624 (Red Hat 4.8.3-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
 >>> import numpy as np
 >>> a=np.ma.array([0, 1], dtype=np.int8, mask=[1, 0])
 >>> a
masked_array(data = [-- 1],
              mask = [ True False],
        fill_value = 999999)

 >>> a.data
array([0, 1], dtype=int8)
 >>> a.filled()
array([63,  1], dtype=int8)         <------- Why 63?
 >>>

What do you think?

George