'**SUMMARY**
Invert (negative) the image note that this can also be done with the
unary minus (-) operator. For binary image this turns black into white and white into black (i.e. white is the new black).
**RETURNS**
The opposite of the current image.
**EXAMPLE**
>>> img  = Image("polar_bear_in_the_snow.png")
>>> img.invert().save("black_bear_at_night.png")
**SEE ALSO**
:py:meth:`binarize`'

def invert(self):

    return (- self)
