code: def putmask(self, value, blc=(), trc=(), inc=()):
          
          # casa and numpy have opposite flags
          return self._putmask(~value, self._adjustBlc(blc),
                               self._adjustInc(inc))
docs: Put image mask.
  
          Using the arguments blc (bottom left corner), trc (top right corner),
          and inc (stride) it is possible to put a data slice. Not all axes
          need to be specified. Missing values default to begin, end, and 1.
  
          The data should be a numpy array. Its dimensionality must be the same
          as the dimensionality of the image.
          Note that the casacore images use the convention that a mask value
          True means good and False means bad. However, numpy uses the opposite.
          Therefore the mask will be negated, so a numoy masked can be given
          directly.
  
          The mask is not written if the image has no mask and if it the entire
          mask is False. In that case the mask most likely comes from a getmask
          operation on an image without a mask.