Return input as an array with masked data replaced by a fill value.
If a is not a MaskedArray, a itself is returned. If a is a MaskedArray and fill_value is None, fill_value is set to a.fill_value.
| Parameters : | a : MaskedArray or array_like 
 fill_value : scalar, optional 
  | 
|---|---|
| Returns : | a : ndarray 
  | 
See also
Examples
>>> x = np.ma.array(np.arange(9).reshape(3, 3), mask=[[1, 0, 0],
...                                                   [1, 0, 0],
...                                                   [0, 0, 0]])
>>> x.filled()
array([[999999,      1,      2],
       [999999,      4,      5],
       [     6,      7,      8]])