>>> from numpy.ma.core import MaskedArray
>>> import numpy as np
>>> z = np.zeros(5)
>>> z
array([ 0.,  0.,  0.,  0.,  0.])
>>> o = np.ones(5)
>>> o
array([ 1.,  1.,  1.,  1.,  1.])
>>> mz = MaskedArray(z)
>>> mz
masked_array(data = [ 0.  0.  0.  0.  0.],
             mask = False,
       fill_value = 1e+20)

>>> mo = MaskedArray(o)
>>> mo
masked_array(data = [ 1.  1.  1.  1.  1.],
             mask = False,
       fill_value = 1e+20)

>>> mocopy = mo.copy
>>> mocopy()
masked_array(data = [ 1.  1.  1.  1.  1.],
             mask = False,
       fill_value = 1e+20)

>>> mz.copy
<numpy.ma.core._arraymethod object at 0x29fff10>
>>> mocopy()
masked_array(data = [ 0.  0.  0.  0.  0.],
             mask = False,
       fill_value = 1e+20)

>>> mo.copy
<numpy.ma.core._arraymethod object at 0x29fff10>
>>> mocopy()
masked_array(data = [ 1.  1.  1.  1.  1.],
             mask = False,
       fill_value = 1e+20)