code: def _blank_within(self, perimeter):
          
          # Method:
          # scan around the perimeter filling 'up' from each pixel
          # stopping when we reach the other boundary
          for p in perimeter:
              # if we are on the edge of the data then there is nothing to fill
              if p[0] >= self.data.shape[0] or p[1] >= self.data.shape[1]:
                  continue
              # if this pixel is blank then don't fill
              if self.data[p] == 0:
                  continue
  
              # blank this pixel
              self.data[p] = 0
  
              # blank until we reach the other perimeter
              for i in range(p[1]+1, self.data.shape[1]):
                  q = p[0], i
                  # stop when we reach another part of the perimeter
                  if q in perimeter:
                      break
                  # fill everything in between, even inclusions
                  self.data[q] = 0
  
          return
docs: Blank all the pixels within the given perimeter.
  
          Parameters
          ----------
          perimeter : list
              The perimeter of the region.