Combine two masks with the logical_or operator.
The result may be a view on m1 or m2 if the other is nomask (i.e. False).
| Parameters : | m1, m2 : array_like 
 copy : bool, optional 
 shrink : bool, optional 
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|---|---|
| Returns : | mask : output mask 
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| Raises : | ValueError : 
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Examples
>>> m1 = np.ma.make_mask([0, 1, 1, 0])
>>> m2 = np.ma.make_mask([1, 0, 0, 0])
>>> np.ma.mask_or(m1, m2)
array([ True,  True,  True, False], dtype=bool)