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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def aesthetics(cls):
 """ Return all the aesthetics for this geom geoms should not override this method. """

        main = cls.DEFAULT_AES.keys() | cls.REQUIRED_AES
        other = {'group'}
        # Need to recognize both spellings
        if 'color' in main:
            other.add('colour')
        if 'outlier_color' in main:
            other.add('outlier_colour')
        return main | other