code: def invert(self, invert=True):
          
          logger.debug("Applying invert with parameters %s", str(invert))
          if isinstance(invert, (tuple, list)):
              invert = self.xrify_tuples(invert)
              offset = invert.astype(int)
              scale = (-1) ** offset
          elif invert:
              offset = 1
              scale = -1
          attrs = self.data.attrs
          self.data = self.data * scale + offset
          self.data.attrs = attrs
docs: Inverts all the channels of a image according to *invert*.
  
          If invert is a tuple or a list, elementwise invertion is performed,
          otherwise all channels are inverted if *invert* is true (default).
  
          Note: 'Inverting' means that black becomes white, and vice-versa, not
          that the values are negated !